Snap for 10611805 from a23d1fae6c9e206eb78460a2a59a3c5c49020c10 to mainline-extservices-release

Change-Id: Id0b4b7ca4266177daefd8af8be9c9513030ae68d
diff --git a/.github/workflows/python-build-test.yml b/.github/workflows/python-build-test.yml
index 72c7b43..3f20093 100644
--- a/.github/workflows/python-build-test.yml
+++ b/.github/workflows/python-build-test.yml
@@ -16,7 +16,7 @@
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.8", "3.9", "3.10"]
+        python-version: ["3.8", "3.9", "3.10", "3.11"]
       fail-fast: false
 
     steps:
@@ -41,3 +41,30 @@
       run: |
         inv build
         inv build.mkdocs
+  build-rust:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: [ "3.8", "3.9", "3.10" ]
+      fail-fast: false
+    steps:
+      - name: Check out from Git
+        uses: actions/checkout@v3
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install ".[build,test,development,documentation]"
+      - name: Install Rust toolchain
+        uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          components: clippy,rustfmt
+      - name: Rust Lints
+        run: cd rust && cargo fmt --check && cargo clippy --all-targets -- --deny warnings
+      - name: Rust Build
+        run: cd rust && cargo build --all-targets
+      - name: Rust Tests
+        run: cd rust && cargo test
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index 43b6410..97dc64d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,4 @@
 # generated by setuptools_scm
 bumble/_version.py
 .vscode/launch.json
+/.idea
diff --git a/Android.bp b/Android.bp
index 640bded..9cb3d08 100644
--- a/Android.bp
+++ b/Android.bp
@@ -19,6 +19,7 @@
     name: "bumble",
     srcs: [
         "bumble/*.py",
+        "bumble/drivers/*.py",
         "bumble/profiles/*.py",
         "bumble/transport/*.py",
     ],
diff --git a/apps/pair.py b/apps/pair.py
index a7844fe..2cc8188 100644
--- a/apps/pair.py
+++ b/apps/pair.py
@@ -157,6 +157,26 @@
         self.print(f'### PIN: {number:0{digits}}')
         self.print('###-----------------------------------')
 
+    async def get_string(self, max_length: int):
+        await self.update_peer_name()
+
+        # Prompt a PIN (for legacy pairing in classic)
+        self.print('###-----------------------------------')
+        self.print(f'### Pairing with {self.peer_name}')
+        self.print('###-----------------------------------')
+        count = 0
+        while True:
+            response = await self.prompt('>>> Enter PIN (1-6 chars):')
+            if len(response) == 0:
+                count += 1
+                if count > 3:
+                    self.print('too many tries, stopping the pairing')
+                    return None
+
+                self.print('no PIN was entered, try again')
+                continue
+            return response
+
 
 # -----------------------------------------------------------------------------
 async def get_peer_name(peer, mode):
@@ -207,7 +227,7 @@
 
     # Listen for pairing events
     connection.on('pairing_start', on_pairing_start)
-    connection.on('pairing', on_pairing)
+    connection.on('pairing', lambda keys: on_pairing(connection.peer_address, keys))
     connection.on('pairing_failure', on_pairing_failure)
 
     # Listen for encryption changes
@@ -242,9 +262,9 @@
 
 
 # -----------------------------------------------------------------------------
-def on_pairing(keys):
+def on_pairing(address, keys):
     print(color('***-----------------------------------', 'cyan'))
-    print(color('*** Paired!', 'cyan'))
+    print(color(f'*** Paired! (peer identity={address})', 'cyan'))
     keys.print(prefix=color('*** ', 'cyan'))
     print(color('***-----------------------------------', 'cyan'))
     Waiter.instance.terminate()
@@ -283,17 +303,6 @@
         # Create a device to manage the host
         device = Device.from_config_file_with_hci(device_config, hci_source, hci_sink)
 
-        # Set a custom keystore if specified on the command line
-        if keystore_file:
-            device.keystore = JsonKeyStore(namespace=None, filename=keystore_file)
-
-        # Print the existing keys before pairing
-        if print_keys and device.keystore:
-            print(color('@@@-----------------------------------', 'blue'))
-            print(color('@@@ Pairing Keys:', 'blue'))
-            await device.keystore.print(prefix=color('@@@ ', 'blue'))
-            print(color('@@@-----------------------------------', 'blue'))
-
         # Expose a GATT characteristic that can be used to trigger pairing by
         # responding with an authentication error when read
         if mode == 'le':
@@ -323,6 +332,17 @@
         # Get things going
         await device.power_on()
 
+        # Set a custom keystore if specified on the command line
+        if keystore_file:
+            device.keystore = JsonKeyStore.from_device(device, filename=keystore_file)
+
+        # Print the existing keys before pairing
+        if print_keys and device.keystore:
+            print(color('@@@-----------------------------------', 'blue'))
+            print(color('@@@ Pairing Keys:', 'blue'))
+            await device.keystore.print(prefix=color('@@@ ', 'blue'))
+            print(color('@@@-----------------------------------', 'blue'))
+
         # Set up a pairing config factory
         device.pairing_config_factory = lambda connection: PairingConfig(
             sc, mitm, bond, Delegate(mode, connection, io, prompt)
diff --git a/apps/scan.py b/apps/scan.py
index dac7a2c..268912f 100644
--- a/apps/scan.py
+++ b/apps/scan.py
@@ -133,15 +133,16 @@
                 'Bumble', 'F0:F1:F2:F3:F4:F5', hci_source, hci_sink
             )
 
+        await device.power_on()
+
         if keystore_file:
-            keystore = JsonKeyStore(namespace=None, filename=keystore_file)
-            device.keystore = keystore
-        else:
-            resolver = None
+            device.keystore = JsonKeyStore.from_device(device, filename=keystore_file)
 
         if device.keystore:
             resolving_keys = await device.keystore.get_resolving_keys()
             resolver = AddressResolver(resolving_keys)
+        else:
+            resolver = None
 
         printer = AdvertisementPrinter(min_rssi, resolver)
         if raw:
@@ -149,8 +150,6 @@
         else:
             device.on('advertisement', printer.on_advertisement)
 
-        await device.power_on()
-
         if phy is None:
             scanning_phys = [HCI_LE_1M_PHY, HCI_LE_CODED_PHY]
         else:
diff --git a/apps/speaker/__init__.py b/apps/speaker/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/apps/speaker/__init__.py
diff --git a/apps/speaker/logo.svg b/apps/speaker/logo.svg
new file mode 100644
index 0000000..70ef7a9
--- /dev/null
+++ b/apps/speaker/logo.svg
@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!-- Created with Vectornator for iOS (http://vectornator.io/) --><!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg height="100%" style="fill-rule:nonzero;clip-rule:evenodd;stroke-linecap:round;stroke-linejoin:round;" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" xml:space="preserve" width="100%" xmlns:vectornator="http://vectornator.io" version="1.1" viewBox="0 0 745 744.634">
+<metadata>
+<vectornator:setting key="DimensionsVisible" value="1"/>
+<vectornator:setting key="PencilOnly" value="0"/>
+<vectornator:setting key="SnapToPoints" value="0"/>
+<vectornator:setting key="OutlineMode" value="0"/>
+<vectornator:setting key="CMYKEnabledKey" value="0"/>
+<vectornator:setting key="RulersVisible" value="1"/>
+<vectornator:setting key="SnapToEdges" value="0"/>
+<vectornator:setting key="GuidesVisible" value="1"/>
+<vectornator:setting key="DisplayWhiteBackground" value="0"/>
+<vectornator:setting key="doHistoryDisabled" value="0"/>
+<vectornator:setting key="SnapToGuides" value="1"/>
+<vectornator:setting key="TimeLapseWatermarkDisabled" value="0"/>
+<vectornator:setting key="Units" value="Pixels"/>
+<vectornator:setting key="DynamicGuides" value="0"/>
+<vectornator:setting key="IsolateActiveLayer" value="0"/>
+<vectornator:setting key="SnapToGrid" value="0"/>
+</metadata>
+<defs/>
+<g id="Layer 1" vectornator:layerName="Layer 1">
+<path stroke="#000000" stroke-width="18.6464" d="M368.753+729.441L58.8847+550.539L58.8848+192.734L368.753+13.8313L678.621+192.734L678.621+550.539L368.753+729.441Z" fill="#0082fc" stroke-linecap="butt" fill-opacity="0.307489" opacity="1" stroke-linejoin="round"/>
+<g opacity="1">
+<g opacity="1">
+<path stroke="#000000" stroke-width="20" d="M292.873+289.256L442.872+289.256L442.872+539.254L292.873+539.254L292.873+289.256Z" fill="#fcd100" stroke-linecap="butt" opacity="1" stroke-linejoin="round"/>
+<path stroke="#000000" stroke-width="20" d="M292.873+289.256C292.873+247.835+326.452+214.257+367.873+214.257C409.294+214.257+442.872+247.835+442.872+289.256C442.872+330.677+409.294+364.256+367.873+364.256C326.452+364.256+292.873+330.677+292.873+289.256Z" fill="#fcd100" stroke-linecap="butt" opacity="1" stroke-linejoin="round"/>
+<path stroke="#000000" stroke-width="20" d="M292.873+539.254C292.873+497.833+326.452+464.255+367.873+464.255C409.294+464.255+442.872+497.833+442.872+539.254C442.872+580.675+409.294+614.254+367.873+614.254C326.452+614.254+292.873+580.675+292.873+539.254Z" fill="#fcd100" stroke-linecap="butt" opacity="1" stroke-linejoin="round"/>
+<path stroke="#0082fc" stroke-width="0.1" d="M302.873+289.073L432.872+289.073L432.872+539.072L302.873+539.072L302.873+289.073Z" fill="#fcd100" stroke-linecap="butt" opacity="1" stroke-linejoin="round"/>
+</g>
+<path stroke="#000000" stroke-width="0.1" d="M103.161+309.167L226.956+443.903L366.671+309.604L103.161+309.167Z" fill="#0082fc" stroke-linecap="round" opacity="1" stroke-linejoin="round"/>
+<path stroke="#000000" stroke-width="0.1" d="M383.411+307.076L508.887+440.112L650.5+307.507L383.411+307.076Z" fill="#0082fc" stroke-linecap="round" opacity="1" stroke-linejoin="round"/>
+<path stroke="#000000" stroke-width="20" d="M522.045+154.808L229.559+448.882L83.8397+300.104L653.666+302.936L511.759+444.785L223.101+156.114" fill="none" stroke-linecap="round" opacity="1" stroke-linejoin="round"/>
+<path stroke="#000000" stroke-width="61.8698" d="M295.857+418.738L438.9+418.738" fill="none" stroke-linecap="butt" opacity="1" stroke-linejoin="round"/>
+<path stroke="#000000" stroke-width="61.8698" d="M295.857+521.737L438.9+521.737" fill="none" stroke-linecap="butt" opacity="1" stroke-linejoin="round"/>
+<g opacity="1">
+<path stroke="#0082fc" stroke-width="0.1" d="M367.769+667.024L367.821+616.383L403.677+616.336C383.137+626.447+368.263+638.69+367.769+667.024Z" fill="#000000" stroke-linecap="butt" opacity="1" stroke-linejoin="round"/>
+<path stroke="#0082fc" stroke-width="0.1" d="M367.836+667.024L367.784+616.383L331.928+616.336C352.468+626.447+367.341+638.69+367.836+667.024Z" fill="#000000" stroke-linecap="butt" opacity="1" stroke-linejoin="round"/>
+</g>
+</g>
+</g>
+</svg>
diff --git a/apps/speaker/speaker.css b/apps/speaker/speaker.css
new file mode 100644
index 0000000..075068b
--- /dev/null
+++ b/apps/speaker/speaker.css
@@ -0,0 +1,76 @@
+body, h1, h2, h3, h4, h5, h6 {
+    font-family: sans-serif;
+}
+
+#controlsDiv {
+    margin: 6px;
+}
+
+#connectionText {
+    background-color: rgb(239, 89, 75);
+    border: none;
+    border-radius: 4px;
+    padding: 8px;
+    display: inline-block;
+    margin: 4px;
+}
+
+#startButton {
+    padding: 4px;
+    margin: 6px;
+}
+
+#fftCanvas {
+    border-radius: 16px;
+    margin: 6px;
+}
+
+#bandwidthCanvas {
+    border: grey;
+    border-style: solid;
+    border-radius: 8px;
+    margin: 6px;
+}
+
+#streamStateText {
+    background-color: rgb(93, 165, 93);
+    border: none;
+    border-radius: 8px;
+    padding: 10px 20px;
+    display: inline-block;
+    margin: 6px;
+}
+
+#connectionStateText {
+    background-color: rgb(112, 146, 206);
+    border: none;
+    border-radius: 8px;
+    padding: 10px 20px;
+    display: inline-block;
+    margin: 6px;
+}
+
+#propertiesTable {
+    border: grey;
+    border-style: solid;
+    border-radius: 4px;
+    padding: 4px;
+    margin: 6px;
+    margin-left: 0px;
+}
+
+th, td {
+    padding-left: 6px;
+    padding-right: 6px;
+}
+
+.properties td:nth-child(even) {
+    background-color: #D6EEEE;
+    font-family: monospace;
+}
+
+.properties td:nth-child(odd) {
+    font-weight: bold;
+}
+
+.properties tr td:nth-child(2) { width: 150px; }
\ No newline at end of file
diff --git a/apps/speaker/speaker.html b/apps/speaker/speaker.html
new file mode 100644
index 0000000..f68abcc
--- /dev/null
+++ b/apps/speaker/speaker.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Bumble Speaker</title>
+  <script type="text/javascript" src="speaker.js"></script>
+  <link rel="stylesheet" href="speaker.css">
+</head>
+<body>
+  <h1><img src="logo.svg" width=100 height=100 style="vertical-align:middle" alt=""/>Bumble Virtual Speaker</h1>
+  <div id="connectionText"></div>
+  <div id="speaker">
+    <table><tr>
+      <td>
+        <table id="propertiesTable" class="properties">
+          <tr><td>Codec</td><td><span id="codecText"></span></td></tr>
+          <tr><td>Packets</td><td><span id="packetsReceivedText"></span></td></tr>
+          <tr><td>Bytes</td><td><span id="bytesReceivedText"></span></td></tr>
+        </table>
+      </td>
+      <td>
+        <canvas id="bandwidthCanvas" width="500", height="100">Bandwidth Graph</canvas>
+      </td>
+    </tr></table>
+    <span id="streamStateText">IDLE</span>
+    <span id="connectionStateText">NOT CONNECTED</span>
+    <div id="controlsDiv">
+        <button id="audioOnButton">Audio On</button>
+        <span id="audioSupportMessageText"></span>
+    </div>
+    <canvas id="fftCanvas" width="1024", height="300">Audio Frequencies Animation</canvas>
+    <audio id="audio"></audio>
+  </div>
+</body>
+</html>
\ No newline at end of file
diff --git a/apps/speaker/speaker.js b/apps/speaker/speaker.js
new file mode 100644
index 0000000..77cb1ff
--- /dev/null
+++ b/apps/speaker/speaker.js
@@ -0,0 +1,315 @@
+(function () {
+    'use strict';
+
+const channelUrl = ((window.location.protocol === "https:") ? "wss://" : "ws://") + window.location.host + "/channel";
+let channelSocket;
+let connectionText;
+let codecText;
+let packetsReceivedText;
+let bytesReceivedText;
+let streamStateText;
+let connectionStateText;
+let controlsDiv;
+let audioOnButton;
+let mediaSource;
+let sourceBuffer;
+let audioElement;
+let audioContext;
+let audioAnalyzer;
+let audioFrequencyBinCount;
+let audioFrequencyData;
+let packetsReceived = 0;
+let bytesReceived = 0;
+let audioState = "stopped";
+let streamState = "IDLE";
+let audioSupportMessageText;
+let fftCanvas;
+let fftCanvasContext;
+let bandwidthCanvas;
+let bandwidthCanvasContext;
+let bandwidthBinCount;
+let bandwidthBins = [];
+
+const FFT_WIDTH = 800;
+const FFT_HEIGHT = 256;
+const BANDWIDTH_WIDTH = 500;
+const BANDWIDTH_HEIGHT = 100;
+
+function hexToBytes(hex) {
+    return Uint8Array.from(hex.match(/.{1,2}/g).map((byte) => parseInt(byte, 16)));
+}
+
+function init() {
+    initUI();
+    initMediaSource();
+    initAudioElement();
+    initAnalyzer();
+
+    connect();
+}
+
+function initUI() {
+    controlsDiv = document.getElementById("controlsDiv");
+    controlsDiv.style.visibility = "hidden";
+    connectionText = document.getElementById("connectionText");
+    audioOnButton = document.getElementById("audioOnButton");
+    codecText = document.getElementById("codecText");
+    packetsReceivedText = document.getElementById("packetsReceivedText");
+    bytesReceivedText = document.getElementById("bytesReceivedText");
+    streamStateText = document.getElementById("streamStateText");
+    connectionStateText = document.getElementById("connectionStateText");
+    audioSupportMessageText = document.getElementById("audioSupportMessageText");
+
+    audioOnButton.onclick = () => startAudio();
+
+    setConnectionText("");
+
+    requestAnimationFrame(onAnimationFrame);
+}
+
+function initMediaSource() {
+    mediaSource = new MediaSource();
+    mediaSource.onsourceopen = onMediaSourceOpen;
+    mediaSource.onsourceclose = onMediaSourceClose;
+    mediaSource.onsourceended = onMediaSourceEnd;
+}
+
+function initAudioElement() {
+    audioElement = document.getElementById("audio");
+    audioElement.src = URL.createObjectURL(mediaSource);
+    // audioElement.controls = true;
+}
+
+function initAnalyzer() {
+    fftCanvas = document.getElementById("fftCanvas");
+    fftCanvas.width = FFT_WIDTH
+    fftCanvas.height = FFT_HEIGHT
+    fftCanvasContext = fftCanvas.getContext('2d');
+    fftCanvasContext.fillStyle = "rgb(0, 0, 0)";
+    fftCanvasContext.fillRect(0, 0, FFT_WIDTH, FFT_HEIGHT);
+
+    bandwidthCanvas = document.getElementById("bandwidthCanvas");
+    bandwidthCanvas.width = BANDWIDTH_WIDTH
+    bandwidthCanvas.height = BANDWIDTH_HEIGHT
+    bandwidthCanvasContext = bandwidthCanvas.getContext('2d');
+    bandwidthCanvasContext.fillStyle = "rgb(255, 255, 255)";
+    bandwidthCanvasContext.fillRect(0, 0, BANDWIDTH_WIDTH, BANDWIDTH_HEIGHT);
+}
+
+function startAnalyzer() {
+    // FFT
+    if (audioElement.captureStream !== undefined) {
+        audioContext = new AudioContext();
+        audioAnalyzer = audioContext.createAnalyser();
+        audioAnalyzer.fftSize = 128;
+        audioFrequencyBinCount = audioAnalyzer.frequencyBinCount;
+        audioFrequencyData = new Uint8Array(audioFrequencyBinCount);
+        const stream = audioElement.captureStream();
+        const source = audioContext.createMediaStreamSource(stream);
+        source.connect(audioAnalyzer);
+    }
+
+    // Bandwidth
+    bandwidthBinCount = BANDWIDTH_WIDTH / 2;
+    bandwidthBins = [];
+}
+
+function setConnectionText(message) {
+    connectionText.innerText = message;
+    if (message.length == 0) {
+        connectionText.style.display = "none";
+    } else {
+        connectionText.style.display = "inline-block";
+    }
+}
+
+function setStreamState(state) {
+    streamState = state;
+    streamStateText.innerText = streamState;
+}
+
+function onAnimationFrame() {
+    // FFT
+    if (audioAnalyzer !== undefined) {
+        audioAnalyzer.getByteFrequencyData(audioFrequencyData);
+        fftCanvasContext.fillStyle = "rgb(0, 0, 0)";
+        fftCanvasContext.fillRect(0, 0, FFT_WIDTH, FFT_HEIGHT);
+        const barCount = audioFrequencyBinCount;
+        const barWidth = (FFT_WIDTH / audioFrequencyBinCount) - 1;
+        for (let bar = 0; bar < barCount; bar++) {
+            const barHeight = audioFrequencyData[bar];
+            fftCanvasContext.fillStyle = `rgb(${barHeight / 256 * 200 + 50}, 50, ${50 + 2 * bar})`;
+            fftCanvasContext.fillRect(bar * (barWidth + 1), FFT_HEIGHT - barHeight, barWidth, barHeight);
+        }
+    }
+
+    // Bandwidth
+    bandwidthCanvasContext.fillStyle = "rgb(255, 255, 255)";
+    bandwidthCanvasContext.fillRect(0, 0, BANDWIDTH_WIDTH, BANDWIDTH_HEIGHT);
+    bandwidthCanvasContext.fillStyle = `rgb(100, 100, 100)`;
+    for (let t = 0; t < bandwidthBins.length; t++) {
+        const lineHeight = (bandwidthBins[t] / 1000) * BANDWIDTH_HEIGHT;
+        bandwidthCanvasContext.fillRect(t * 2, BANDWIDTH_HEIGHT - lineHeight, 2, lineHeight);
+    }
+
+    // Display again at the next frame
+    requestAnimationFrame(onAnimationFrame);
+}
+
+function onMediaSourceOpen() {
+    console.log(this.readyState);
+    sourceBuffer = mediaSource.addSourceBuffer("audio/aac");
+}
+
+function onMediaSourceClose() {
+    console.log(this.readyState);
+}
+
+function onMediaSourceEnd() {
+    console.log(this.readyState);
+}
+
+async function startAudio() {
+    try {
+        console.log("starting audio...");
+        audioOnButton.disabled = true;
+        audioState = "starting";
+        await audioElement.play();
+        console.log("audio started");
+        audioState = "playing";
+        startAnalyzer();
+    } catch(error) {
+        console.error(`play failed: ${error}`);
+        audioState = "stopped";
+        audioOnButton.disabled = false;
+    }
+}
+
+function onAudioPacket(packet) {
+    if (audioState != "stopped") {
+        // Queue the audio packet.
+        sourceBuffer.appendBuffer(packet);
+    }
+
+    packetsReceived += 1;
+    packetsReceivedText.innerText = packetsReceived;
+    bytesReceived += packet.byteLength;
+    bytesReceivedText.innerText = bytesReceived;
+
+    bandwidthBins[bandwidthBins.length] = packet.byteLength;
+    if (bandwidthBins.length > bandwidthBinCount) {
+        bandwidthBins.shift();
+    }
+}
+
+function onChannelOpen() {
+    console.log('channel OPEN');
+    setConnectionText("");
+    controlsDiv.style.visibility = "visible";
+
+    // Handshake with the backend.
+    sendMessage({
+        type: "hello"
+    });
+}
+
+function onChannelClose() {
+    console.log('channel CLOSED');
+    setConnectionText("Connection to CLI app closed, restart it and reload this page.");
+    controlsDiv.style.visibility = "hidden";
+}
+
+function onChannelError(error) {
+    console.log(`channel ERROR: ${error}`);
+    setConnectionText(`Connection to CLI app error ({${error}}), restart it and reload this page.`);
+    controlsDiv.style.visibility = "hidden";
+}
+
+function onChannelMessage(message) {
+    if (typeof message.data === 'string' || message.data instanceof String) {
+        // JSON message.
+        const jsonMessage = JSON.parse(message.data);
+        console.log(`channel MESSAGE: ${message.data}`);
+
+        // Dispatch the message.
+        const handlerName = `on${jsonMessage.type.charAt(0).toUpperCase()}${jsonMessage.type.slice(1)}Message`
+        const handler = messageHandlers[handlerName];
+        if (handler !== undefined) {
+            const params = jsonMessage.params;
+            if (params === undefined) {
+                params = {};
+            }
+            handler(params);
+        } else {
+            console.warn(`unhandled message: ${jsonMessage.type}`)
+        }
+    } else {
+        // BINARY audio data.
+        onAudioPacket(message.data);
+    }
+}
+
+function onHelloMessage(params) {
+    codecText.innerText = params.codec;
+    if (params.codec != "aac") {
+        audioOnButton.disabled = true;
+        audioSupportMessageText.innerText = "Only AAC can be played, audio will be disabled";
+        audioSupportMessageText.style.display = "inline-block";
+    } else {
+        audioSupportMessageText.innerText = "";
+        audioSupportMessageText.style.display = "none";
+    }
+    if (params.streamState) {
+        setStreamState(params.streamState);
+    }
+}
+
+function onStartMessage(params) {
+    setStreamState("STARTED");
+}
+
+function onStopMessage(params) {
+    setStreamState("STOPPED");
+}
+
+function onSuspendMessage(params) {
+    setStreamState("SUSPENDED");
+}
+
+function onConnectionMessage(params) {
+    connectionStateText.innerText = `CONNECTED: ${params.peer_name} (${params.peer_address})`;
+}
+
+function onDisconnectionMessage(params) {
+    connectionStateText.innerText = "DISCONNECTED";
+}
+
+function sendMessage(message) {
+    channelSocket.send(JSON.stringify(message));
+}
+
+function connect() {
+    console.log("connecting to CLI app");
+
+    channelSocket = new WebSocket(channelUrl);
+    channelSocket.binaryType = "arraybuffer";
+    channelSocket.onopen = onChannelOpen;
+    channelSocket.onclose = onChannelClose;
+    channelSocket.onerror = onChannelError;
+    channelSocket.onmessage = onChannelMessage;
+}
+
+const messageHandlers = {
+    onHelloMessage,
+    onStartMessage,
+    onStopMessage,
+    onSuspendMessage,
+    onConnectionMessage,
+    onDisconnectionMessage
+}
+
+window.onload = (event) => {
+    init();
+}
+
+}());
\ No newline at end of file
diff --git a/apps/speaker/speaker.py b/apps/speaker/speaker.py
new file mode 100644
index 0000000..a2907d4
--- /dev/null
+++ b/apps/speaker/speaker.py
@@ -0,0 +1,747 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+from __future__ import annotations
+import asyncio
+import asyncio.subprocess
+from importlib import resources
+import enum
+import json
+import os
+import logging
+import pathlib
+import subprocess
+from typing import Dict, List, Optional
+import weakref
+
+import click
+import aiohttp
+from aiohttp import web
+
+import bumble
+from bumble.colors import color
+from bumble.core import BT_BR_EDR_TRANSPORT, CommandTimeoutError
+from bumble.device import Connection, Device, DeviceConfiguration
+from bumble.hci import HCI_StatusError
+from bumble.pairing import PairingConfig
+from bumble.sdp import ServiceAttribute
+from bumble.transport import open_transport
+from bumble.avdtp import (
+    AVDTP_AUDIO_MEDIA_TYPE,
+    Listener,
+    MediaCodecCapabilities,
+    MediaPacket,
+    Protocol,
+)
+from bumble.a2dp import (
+    MPEG_2_AAC_LC_OBJECT_TYPE,
+    make_audio_sink_service_sdp_records,
+    A2DP_SBC_CODEC_TYPE,
+    A2DP_MPEG_2_4_AAC_CODEC_TYPE,
+    SBC_MONO_CHANNEL_MODE,
+    SBC_DUAL_CHANNEL_MODE,
+    SBC_SNR_ALLOCATION_METHOD,
+    SBC_LOUDNESS_ALLOCATION_METHOD,
+    SBC_STEREO_CHANNEL_MODE,
+    SBC_JOINT_STEREO_CHANNEL_MODE,
+    SbcMediaCodecInformation,
+    AacMediaCodecInformation,
+)
+from bumble.utils import AsyncRunner
+from bumble.codecs import AacAudioRtpPacket
+
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+
+# -----------------------------------------------------------------------------
+# Constants
+# -----------------------------------------------------------------------------
+DEFAULT_UI_PORT = 7654
+
+# -----------------------------------------------------------------------------
+class AudioExtractor:
+    @staticmethod
+    def create(codec: str):
+        if codec == 'aac':
+            return AacAudioExtractor()
+        if codec == 'sbc':
+            return SbcAudioExtractor()
+
+    def extract_audio(self, packet: MediaPacket) -> bytes:
+        raise NotImplementedError()
+
+
+# -----------------------------------------------------------------------------
+class AacAudioExtractor:
+    def extract_audio(self, packet: MediaPacket) -> bytes:
+        return AacAudioRtpPacket(packet.payload).to_adts()
+
+
+# -----------------------------------------------------------------------------
+class SbcAudioExtractor:
+    def extract_audio(self, packet: MediaPacket) -> bytes:
+        # header = packet.payload[0]
+        # fragmented = header >> 7
+        # start = (header >> 6) & 0x01
+        # last = (header >> 5) & 0x01
+        # number_of_frames = header & 0x0F
+
+        # TODO: support fragmented payloads
+        return packet.payload[1:]
+
+
+# -----------------------------------------------------------------------------
+class Output:
+    async def start(self) -> None:
+        pass
+
+    async def stop(self) -> None:
+        pass
+
+    async def suspend(self) -> None:
+        pass
+
+    async def on_connection(self, connection: Connection) -> None:
+        pass
+
+    async def on_disconnection(self, reason: int) -> None:
+        pass
+
+    def on_rtp_packet(self, packet: MediaPacket) -> None:
+        pass
+
+
+# -----------------------------------------------------------------------------
+class FileOutput(Output):
+    filename: str
+    codec: str
+    extractor: AudioExtractor
+
+    def __init__(self, filename, codec):
+        self.filename = filename
+        self.codec = codec
+        self.file = open(filename, 'wb')
+        self.extractor = AudioExtractor.create(codec)
+
+    def on_rtp_packet(self, packet: MediaPacket) -> None:
+        self.file.write(self.extractor.extract_audio(packet))
+
+
+# -----------------------------------------------------------------------------
+class QueuedOutput(Output):
+    MAX_QUEUE_SIZE = 32768
+
+    packets: asyncio.Queue
+    extractor: AudioExtractor
+    packet_pump_task: Optional[asyncio.Task]
+    started: bool
+
+    def __init__(self, extractor):
+        self.extractor = extractor
+        self.packets = asyncio.Queue()
+        self.packet_pump_task = None
+        self.started = False
+
+    async def start(self):
+        if self.started:
+            return
+
+        self.packet_pump_task = asyncio.create_task(self.pump_packets())
+
+    async def pump_packets(self):
+        while True:
+            packet = await self.packets.get()
+            await self.on_audio_packet(packet)
+
+    async def on_audio_packet(self, packet: bytes) -> None:
+        pass
+
+    def on_rtp_packet(self, packet: MediaPacket) -> None:
+        if self.packets.qsize() > self.MAX_QUEUE_SIZE:
+            logger.debug("queue full, dropping")
+            return
+
+        self.packets.put_nowait(self.extractor.extract_audio(packet))
+
+
+# -----------------------------------------------------------------------------
+class WebSocketOutput(QueuedOutput):
+    def __init__(self, codec, send_audio, send_message):
+        super().__init__(AudioExtractor.create(codec))
+        self.send_audio = send_audio
+        self.send_message = send_message
+
+    async def on_connection(self, connection: Connection) -> None:
+        try:
+            await connection.request_remote_name()
+        except HCI_StatusError:
+            pass
+        peer_name = '' if connection.peer_name is None else connection.peer_name
+        peer_address = str(connection.peer_address).replace('/P', '')
+        await self.send_message(
+            'connection',
+            peer_address=peer_address,
+            peer_name=peer_name,
+        )
+
+    async def on_disconnection(self, reason) -> None:
+        await self.send_message('disconnection')
+
+    async def on_audio_packet(self, packet: bytes) -> None:
+        await self.send_audio(packet)
+
+    async def start(self):
+        await super().start()
+        await self.send_message('start')
+
+    async def stop(self):
+        await super().stop()
+        await self.send_message('stop')
+
+    async def suspend(self):
+        await super().suspend()
+        await self.send_message('suspend')
+
+
+# -----------------------------------------------------------------------------
+class FfplayOutput(QueuedOutput):
+    MAX_QUEUE_SIZE = 32768
+
+    subprocess: Optional[asyncio.subprocess.Process]
+    ffplay_task: Optional[asyncio.Task]
+
+    def __init__(self) -> None:
+        super().__init__(AacAudioExtractor())
+        self.subprocess = None
+        self.ffplay_task = None
+
+    async def start(self):
+        if self.started:
+            return
+
+        await super().start()
+
+        self.subprocess = await asyncio.create_subprocess_shell(
+            'ffplay -acodec aac pipe:0',
+            stdin=asyncio.subprocess.PIPE,
+            stdout=asyncio.subprocess.PIPE,
+            stderr=asyncio.subprocess.PIPE,
+        )
+
+        self.ffplay_task = asyncio.create_task(self.monitor_ffplay())
+
+    async def stop(self):
+        # TODO
+        pass
+
+    async def suspend(self):
+        # TODO
+        pass
+
+    async def monitor_ffplay(self):
+        async def read_stream(name, stream):
+            while True:
+                data = await stream.read()
+                logger.debug(f'{name}:', data)
+
+        await asyncio.wait(
+            [
+                asyncio.create_task(
+                    read_stream('[ffplay stdout]', self.subprocess.stdout)
+                ),
+                asyncio.create_task(
+                    read_stream('[ffplay stderr]', self.subprocess.stderr)
+                ),
+                asyncio.create_task(self.subprocess.wait()),
+            ]
+        )
+        logger.debug("FFPLAY done")
+
+    async def on_audio_packet(self, packet):
+        try:
+            self.subprocess.stdin.write(packet)
+        except Exception:
+            logger.warning('!!!! exception while sending audio to ffplay pipe')
+
+
+# -----------------------------------------------------------------------------
+class UiServer:
+    speaker: weakref.ReferenceType[Speaker]
+    port: int
+
+    def __init__(self, speaker: Speaker, port: int) -> None:
+        self.speaker = weakref.ref(speaker)
+        self.port = port
+        self.channel_socket = None
+
+    async def start_http(self) -> None:
+        """Start the UI HTTP server."""
+
+        app = web.Application()
+        app.add_routes(
+            [
+                web.get('/', self.get_static),
+                web.get('/speaker.html', self.get_static),
+                web.get('/speaker.js', self.get_static),
+                web.get('/speaker.css', self.get_static),
+                web.get('/logo.svg', self.get_static),
+                web.get('/channel', self.get_channel),
+            ]
+        )
+
+        runner = web.AppRunner(app)
+        await runner.setup()
+        site = web.TCPSite(runner, 'localhost', self.port)
+        print('UI HTTP server at ' + color(f'http://127.0.0.1:{self.port}', 'green'))
+        await site.start()
+
+    async def get_static(self, request):
+        path = request.path
+        if path == '/':
+            path = '/speaker.html'
+        if path.endswith('.html'):
+            content_type = 'text/html'
+        elif path.endswith('.js'):
+            content_type = 'text/javascript'
+        elif path.endswith('.css'):
+            content_type = 'text/css'
+        elif path.endswith('.svg'):
+            content_type = 'image/svg+xml'
+        else:
+            content_type = 'text/plain'
+        text = (
+            resources.files("bumble.apps.speaker")
+            .joinpath(pathlib.Path(path).relative_to('/'))
+            .read_text(encoding="utf-8")
+        )
+        return aiohttp.web.Response(text=text, content_type=content_type)
+
+    async def get_channel(self, request):
+        ws = web.WebSocketResponse()
+        await ws.prepare(request)
+
+        # Process messages until the socket is closed.
+        self.channel_socket = ws
+        async for message in ws:
+            if message.type == aiohttp.WSMsgType.TEXT:
+                logger.debug(f'<<< received message: {message.data}')
+                await self.on_message(message.data)
+            elif message.type == aiohttp.WSMsgType.ERROR:
+                logger.debug(
+                    f'channel connection closed with exception {ws.exception()}'
+                )
+
+        self.channel_socket = None
+        logger.debug('--- channel connection closed')
+
+        return ws
+
+    async def on_message(self, message_str: str):
+        # Parse the message as JSON
+        message = json.loads(message_str)
+
+        # Dispatch the message
+        message_type = message['type']
+        message_params = message.get('params', {})
+        handler = getattr(self, f'on_{message_type}_message')
+        if handler:
+            await handler(**message_params)
+
+    async def on_hello_message(self):
+        await self.send_message(
+            'hello',
+            bumble_version=bumble.__version__,
+            codec=self.speaker().codec,
+            streamState=self.speaker().stream_state.name,
+        )
+        if connection := self.speaker().connection:
+            await self.send_message(
+                'connection',
+                peer_address=str(connection.peer_address).replace('/P', ''),
+                peer_name=connection.peer_name,
+            )
+
+    async def send_message(self, message_type: str, **kwargs) -> None:
+        if self.channel_socket is None:
+            return
+
+        message = {'type': message_type, 'params': kwargs}
+        await self.channel_socket.send_json(message)
+
+    async def send_audio(self, data: bytes) -> None:
+        if self.channel_socket is None:
+            return
+
+        try:
+            await self.channel_socket.send_bytes(data)
+        except Exception as error:
+            logger.warning(f'exception while sending audio packet: {error}')
+
+
+# -----------------------------------------------------------------------------
+class Speaker:
+    class StreamState(enum.Enum):
+        IDLE = 0
+        STOPPED = 1
+        STARTED = 2
+        SUSPENDED = 3
+
+    def __init__(self, device_config, transport, codec, discover, outputs, ui_port):
+        self.device_config = device_config
+        self.transport = transport
+        self.codec = codec
+        self.discover = discover
+        self.ui_port = ui_port
+        self.device = None
+        self.connection = None
+        self.listener = None
+        self.packets_received = 0
+        self.bytes_received = 0
+        self.stream_state = Speaker.StreamState.IDLE
+        self.outputs = []
+        for output in outputs:
+            if output == '@ffplay':
+                self.outputs.append(FfplayOutput())
+                continue
+
+            # Default to FileOutput
+            self.outputs.append(FileOutput(output, codec))
+
+        # Create an HTTP server for the UI
+        self.ui_server = UiServer(speaker=self, port=ui_port)
+
+    def sdp_records(self) -> Dict[int, List[ServiceAttribute]]:
+        service_record_handle = 0x00010001
+        return {
+            service_record_handle: make_audio_sink_service_sdp_records(
+                service_record_handle
+            )
+        }
+
+    def codec_capabilities(self) -> MediaCodecCapabilities:
+        if self.codec == 'aac':
+            return self.aac_codec_capabilities()
+
+        if self.codec == 'sbc':
+            return self.sbc_codec_capabilities()
+
+        raise RuntimeError('unsupported codec')
+
+    def aac_codec_capabilities(self) -> MediaCodecCapabilities:
+        return MediaCodecCapabilities(
+            media_type=AVDTP_AUDIO_MEDIA_TYPE,
+            media_codec_type=A2DP_MPEG_2_4_AAC_CODEC_TYPE,
+            media_codec_information=AacMediaCodecInformation.from_lists(
+                object_types=[MPEG_2_AAC_LC_OBJECT_TYPE],
+                sampling_frequencies=[48000, 44100],
+                channels=[1, 2],
+                vbr=1,
+                bitrate=256000,
+            ),
+        )
+
+    def sbc_codec_capabilities(self) -> MediaCodecCapabilities:
+        return MediaCodecCapabilities(
+            media_type=AVDTP_AUDIO_MEDIA_TYPE,
+            media_codec_type=A2DP_SBC_CODEC_TYPE,
+            media_codec_information=SbcMediaCodecInformation.from_lists(
+                sampling_frequencies=[48000, 44100, 32000, 16000],
+                channel_modes=[
+                    SBC_MONO_CHANNEL_MODE,
+                    SBC_DUAL_CHANNEL_MODE,
+                    SBC_STEREO_CHANNEL_MODE,
+                    SBC_JOINT_STEREO_CHANNEL_MODE,
+                ],
+                block_lengths=[4, 8, 12, 16],
+                subbands=[4, 8],
+                allocation_methods=[
+                    SBC_LOUDNESS_ALLOCATION_METHOD,
+                    SBC_SNR_ALLOCATION_METHOD,
+                ],
+                minimum_bitpool_value=2,
+                maximum_bitpool_value=53,
+            ),
+        )
+
+    async def dispatch_to_outputs(self, function):
+        for output in self.outputs:
+            await function(output)
+
+    def on_bluetooth_connection(self, connection):
+        print(f'Connection: {connection}')
+        self.connection = connection
+        connection.on('disconnection', self.on_bluetooth_disconnection)
+        AsyncRunner.spawn(
+            self.dispatch_to_outputs(lambda output: output.on_connection(connection))
+        )
+
+    def on_bluetooth_disconnection(self, reason):
+        print(f'Disconnection ({reason})')
+        self.connection = None
+        AsyncRunner.spawn(self.advertise())
+        AsyncRunner.spawn(
+            self.dispatch_to_outputs(lambda output: output.on_disconnection(reason))
+        )
+
+    def on_avdtp_connection(self, protocol):
+        print('Audio Stream Open')
+
+        # Add a sink endpoint to the server
+        sink = protocol.add_sink(self.codec_capabilities())
+        sink.on('start', self.on_sink_start)
+        sink.on('stop', self.on_sink_stop)
+        sink.on('suspend', self.on_sink_suspend)
+        sink.on('configuration', lambda: self.on_sink_configuration(sink.configuration))
+        sink.on('rtp_packet', self.on_rtp_packet)
+        sink.on('rtp_channel_open', self.on_rtp_channel_open)
+        sink.on('rtp_channel_close', self.on_rtp_channel_close)
+
+        # Listen for close events
+        protocol.on('close', self.on_avdtp_close)
+
+        # Discover all endpoints on the remote device is requested
+        if self.discover:
+            AsyncRunner.spawn(self.discover_remote_endpoints(protocol))
+
+    def on_avdtp_close(self):
+        print("Audio Stream Closed")
+
+    def on_sink_start(self):
+        print("Sink Started\u001b[0K")
+        self.stream_state = self.StreamState.STARTED
+        AsyncRunner.spawn(self.dispatch_to_outputs(lambda output: output.start()))
+
+    def on_sink_stop(self):
+        print("Sink Stopped\u001b[0K")
+        self.stream_state = self.StreamState.STOPPED
+        AsyncRunner.spawn(self.dispatch_to_outputs(lambda output: output.stop()))
+
+    def on_sink_suspend(self):
+        print("Sink Suspended\u001b[0K")
+        self.stream_state = self.StreamState.SUSPENDED
+        AsyncRunner.spawn(self.dispatch_to_outputs(lambda output: output.suspend()))
+
+    def on_sink_configuration(self, config):
+        print("Sink Configuration:")
+        print('\n'.join(["  " + str(capability) for capability in config]))
+
+    def on_rtp_channel_open(self):
+        print("RTP Channel Open")
+
+    def on_rtp_channel_close(self):
+        print("RTP Channel Closed")
+        self.stream_state = self.StreamState.IDLE
+
+    def on_rtp_packet(self, packet):
+        self.packets_received += 1
+        self.bytes_received += len(packet.payload)
+        print(
+            f'[{self.bytes_received} bytes in {self.packets_received} packets] {packet}',
+            end='\r',
+        )
+
+        for output in self.outputs:
+            output.on_rtp_packet(packet)
+
+    async def advertise(self):
+        await self.device.set_discoverable(True)
+        await self.device.set_connectable(True)
+
+    async def connect(self, address):
+        # Connect to the source
+        print(f'=== Connecting to {address}...')
+        connection = await self.device.connect(address, transport=BT_BR_EDR_TRANSPORT)
+        print(f'=== Connected to {connection.peer_address}')
+
+        # Request authentication
+        print('*** Authenticating...')
+        await connection.authenticate()
+        print('*** Authenticated')
+
+        # Enable encryption
+        print('*** Enabling encryption...')
+        await connection.encrypt()
+        print('*** Encryption on')
+
+        protocol = await Protocol.connect(connection)
+        self.listener.set_server(connection, protocol)
+        self.on_avdtp_connection(protocol)
+
+    async def discover_remote_endpoints(self, protocol):
+        endpoints = await protocol.discover_remote_endpoints()
+        print(f'@@@ Found {len(endpoints)} endpoints')
+        for endpoint in endpoints:
+            print('@@@', endpoint)
+
+    async def run(self, connect_address):
+        await self.ui_server.start_http()
+        self.outputs.append(
+            WebSocketOutput(
+                self.codec, self.ui_server.send_audio, self.ui_server.send_message
+            )
+        )
+
+        async with await open_transport(self.transport) as (hci_source, hci_sink):
+            # Create a device
+            device_config = DeviceConfiguration()
+            if self.device_config:
+                device_config.load_from_file(self.device_config)
+            else:
+                device_config.name = "Bumble Speaker"
+                device_config.class_of_device = 0x240414
+                device_config.keystore = "JsonKeyStore"
+
+            device_config.classic_enabled = True
+            device_config.le_enabled = False
+            self.device = Device.from_config_with_hci(
+                device_config, hci_source, hci_sink
+            )
+
+            # Setup the SDP to expose the sink service
+            self.device.sdp_service_records = self.sdp_records()
+
+            # Don't require MITM when pairing.
+            self.device.pairing_config_factory = lambda connection: PairingConfig(
+                mitm=False
+            )
+
+            # Start the controller
+            await self.device.power_on()
+
+            # Print some of the config/properties
+            print("Speaker Name:", color(device_config.name, 'yellow'))
+            print(
+                "Speaker Bluetooth Address:",
+                color(
+                    self.device.public_address.to_string(with_type_qualifier=False),
+                    'yellow',
+                ),
+            )
+
+            # Listen for Bluetooth connections
+            self.device.on('connection', self.on_bluetooth_connection)
+
+            # Create a listener to wait for AVDTP connections
+            self.listener = Listener(Listener.create_registrar(self.device))
+            self.listener.on('connection', self.on_avdtp_connection)
+
+            print(f'Speaker ready to play, codec={color(self.codec, "cyan")}')
+
+            if connect_address:
+                # Connect to the source
+                try:
+                    await self.connect(connect_address)
+                except CommandTimeoutError:
+                    print(color("Connection timed out", "red"))
+                    return
+            else:
+                # Start being discoverable and connectable
+                print("Waiting for connection...")
+                await self.advertise()
+
+            await hci_source.wait_for_termination()
+
+        for output in self.outputs:
+            await output.stop()
+
+
+# -----------------------------------------------------------------------------
+@click.group()
+@click.pass_context
+def speaker_cli(ctx, device_config):
+    ctx.ensure_object(dict)
+    ctx.obj['device_config'] = device_config
+
+
+@click.command()
+@click.option(
+    '--codec', type=click.Choice(['sbc', 'aac']), default='aac', show_default=True
+)
+@click.option(
+    '--discover', is_flag=True, help='Discover remote endpoints once connected'
+)
+@click.option(
+    '--output',
+    multiple=True,
+    metavar='NAME',
+    help=(
+        'Send audio to this named output '
+        '(may be used more than once for multiple outputs)'
+    ),
+)
+@click.option(
+    '--ui-port',
+    'ui_port',
+    metavar='HTTP_PORT',
+    default=DEFAULT_UI_PORT,
+    show_default=True,
+    help='HTTP port for the UI server',
+)
+@click.option(
+    '--connect',
+    'connect_address',
+    metavar='ADDRESS_OR_NAME',
+    help='Address or name to connect to',
+)
+@click.option('--device-config', metavar='FILENAME', help='Device configuration file')
+@click.argument('transport')
+def speaker(
+    transport, codec, connect_address, discover, output, ui_port, device_config
+):
+    """Run the speaker."""
+
+    # ffplay only works with AAC for now
+    if codec != 'aac' and '@ffplay' in output:
+        print(
+            color(
+                f'{codec} not supported with @ffplay output, '
+                '@ffplay output will be skipped',
+                'yellow',
+            )
+        )
+        output = list(filter(lambda x: x != '@ffplay', output))
+
+    if '@ffplay' in output:
+        # Check if ffplay is installed
+        try:
+            subprocess.run(['ffplay', '-version'], capture_output=True, check=True)
+        except FileNotFoundError:
+            print(
+                color('ffplay not installed, @ffplay output will be disabled', 'yellow')
+            )
+            output = list(filter(lambda x: x != '@ffplay', output))
+
+    asyncio.run(
+        Speaker(device_config, transport, codec, discover, output, ui_port).run(
+            connect_address
+        )
+    )
+
+
+# -----------------------------------------------------------------------------
+def main():
+    logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'WARNING').upper())
+    speaker()
+
+
+# -----------------------------------------------------------------------------
+if __name__ == "__main__":
+    main()  # pylint: disable=no-value-for-parameter
diff --git a/apps/unbond.py b/apps/unbond.py
index 105d9a4..5ffd746 100644
--- a/apps/unbond.py
+++ b/apps/unbond.py
@@ -22,40 +22,58 @@
 
 from bumble.device import Device
 from bumble.keys import JsonKeyStore
+from bumble.transport import open_transport
+
+# -----------------------------------------------------------------------------
+async def unbond_with_keystore(keystore, address):
+    if address is None:
+        return await keystore.print()
+
+    try:
+        await keystore.delete(address)
+    except KeyError:
+        print('!!! pairing not found')
 
 
 # -----------------------------------------------------------------------------
-async def unbond(keystore_file, device_config, address):
-    # Create a device to manage the host
-    device = Device.from_config_file(device_config)
-
-    # Get all entries in the keystore
+async def unbond(keystore_file, device_config, hci_transport, address):
+    # With a keystore file, we can instantiate the keystore directly
     if keystore_file:
-        keystore = JsonKeyStore(None, keystore_file)
-    else:
-        keystore = device.keystore
+        return await unbond_with_keystore(JsonKeyStore(None, keystore_file), address)
 
-    if keystore is None:
-        print('no keystore')
-        return
+    # Without a keystore file, we need to obtain the keystore from the device
+    async with await open_transport(hci_transport) as (hci_source, hci_sink):
+        # Create a device to manage the host
+        device = Device.from_config_file_with_hci(device_config, hci_source, hci_sink)
 
-    if address is None:
-        await keystore.print()
-    else:
-        try:
-            await keystore.delete(address)
-        except KeyError:
-            print('!!! pairing not found')
+        # Power-on the device to ensure we have a key store
+        await device.power_on()
+
+        return await unbond_with_keystore(device.keystore, address)
 
 
 # -----------------------------------------------------------------------------
 @click.command()
-@click.option('--keystore-file', help='File in which to store the pairing keys')
-@click.argument('device-config')
+@click.option('--keystore-file', help='File in which the pairing keys are stored')
+@click.option('--hci-transport', help='HCI transport for the controller')
+@click.argument('device-config', required=False)
 @click.argument('address', required=False)
-def main(keystore_file, device_config, address):
+def main(keystore_file, hci_transport, device_config, address):
+    """
+    Remove pairing keys for a device, given its address.
+
+    If no keystore file is specified, the --hci-transport option must be used to
+    connect to a controller, so that the keystore for that controller can be
+    instantiated.
+    If no address is passed, the existing pairing keys for all addresses are printed.
+    """
     logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'INFO').upper())
-    asyncio.run(unbond(keystore_file, device_config, address))
+
+    if not keystore_file and not hci_transport:
+        print('either --keystore-file or --hci-transport must be specified.')
+        return
+
+    asyncio.run(unbond(keystore_file, device_config, hci_transport, address))
 
 
 # -----------------------------------------------------------------------------
diff --git a/bumble/a2dp.py b/bumble/a2dp.py
index 772846a..eeecb1e 100644
--- a/bumble/a2dp.py
+++ b/bumble/a2dp.py
@@ -432,6 +432,7 @@
                 cls.SAMPLING_FREQUENCY_BITS[x] for x in sampling_frequencies
             ),
             channels=sum(cls.CHANNELS_BITS[x] for x in channels),
+            rfa=0,
             vbr=vbr,
             bitrate=bitrate,
         )
diff --git a/bumble/avdtp.py b/bumble/avdtp.py
index 238036d..3988f30 100644
--- a/bumble/avdtp.py
+++ b/bumble/avdtp.py
@@ -1207,7 +1207,7 @@
 
 
 # -----------------------------------------------------------------------------
-class Protocol:
+class Protocol(EventEmitter):
     SINGLE_PACKET = 0
     START_PACKET = 1
     CONTINUE_PACKET = 2
@@ -1234,6 +1234,7 @@
         return protocol
 
     def __init__(self, l2cap_channel, version=(1, 3)):
+        super().__init__()
         self.l2cap_channel = l2cap_channel
         self.version = version
         self.rtx_sig_timer = AVDTP_DEFAULT_RTX_SIG_TIMER
@@ -1250,6 +1251,7 @@
         # Register to receive PDUs from the channel
         l2cap_channel.sink = self.on_pdu
         l2cap_channel.on('open', self.on_l2cap_channel_open)
+        l2cap_channel.on('close', self.on_l2cap_channel_close)
 
     def get_local_endpoint_by_seid(self, seid):
         if 0 < seid <= len(self.local_endpoints):
@@ -1392,11 +1394,18 @@
 
     def on_l2cap_connection(self, channel):
         # Forward the channel to the endpoint that's expecting it
-        if self.channel_acceptor:
-            self.channel_acceptor.on_l2cap_connection(channel)
+        if self.channel_acceptor is None:
+            logger.warning(color('!!! l2cap connection with no acceptor', 'red'))
+            return
+        self.channel_acceptor.on_l2cap_connection(channel)
 
     def on_l2cap_channel_open(self):
         logger.debug(color('<<< L2CAP channel open', 'magenta'))
+        self.emit('open')
+
+    def on_l2cap_channel_close(self):
+        logger.debug(color('<<< L2CAP channel close', 'magenta'))
+        self.emit('close')
 
     def send_message(self, transaction_label, message):
         logger.debug(
@@ -1651,6 +1660,10 @@
     def set_server(self, connection, server):
         self.servers[connection.handle] = server
 
+    def remove_server(self, connection):
+        if connection.handle in self.servers:
+            del self.servers[connection.handle]
+
     def __init__(self, registrar, version=(1, 3)):
         super().__init__()
         self.version = version
@@ -1669,11 +1682,17 @@
         else:
             # This is a new command/response channel
             def on_channel_open():
+                logger.debug('setting up new Protocol for the connection')
                 server = Protocol(channel, self.version)
                 self.set_server(channel.connection, server)
                 self.emit('connection', server)
 
+            def on_channel_close():
+                logger.debug('removing Protocol for the connection')
+                self.remove_server(channel.connection)
+
             channel.on('open', on_channel_open)
+            channel.on('close', on_channel_close)
 
 
 # -----------------------------------------------------------------------------
@@ -1967,11 +1986,12 @@
 
 
 # -----------------------------------------------------------------------------
-class LocalStreamEndPoint(StreamEndPoint):
+class LocalStreamEndPoint(StreamEndPoint, EventEmitter):
     def __init__(
         self, protocol, seid, media_type, tsep, capabilities, configuration=None
     ):
-        super().__init__(seid, media_type, tsep, 0, capabilities)
+        StreamEndPoint.__init__(self, seid, media_type, tsep, 0, capabilities)
+        EventEmitter.__init__(self)
         self.protocol = protocol
         self.configuration = configuration if configuration is not None else []
         self.stream = None
@@ -1988,40 +2008,47 @@
     def on_reconfigure_command(self, command):
         pass
 
+    def on_set_configuration_command(self, configuration):
+        logger.debug(
+            '<<< received configuration: '
+            f'{",".join([str(capability) for capability in configuration])}'
+        )
+        self.configuration = configuration
+        self.emit('configuration')
+
     def on_get_configuration_command(self):
         return Get_Configuration_Response(self.configuration)
 
     def on_open_command(self):
-        pass
+        self.emit('open')
 
     def on_start_command(self):
-        pass
+        self.emit('start')
 
     def on_suspend_command(self):
-        pass
+        self.emit('suspend')
 
     def on_close_command(self):
-        pass
+        self.emit('close')
 
     def on_abort_command(self):
-        pass
+        self.emit('abort')
 
     def on_rtp_channel_open(self):
-        pass
+        self.emit('rtp_channel_open')
 
     def on_rtp_channel_close(self):
-        pass
+        self.emit('rtp_channel_close')
 
 
 # -----------------------------------------------------------------------------
-class LocalSource(LocalStreamEndPoint, EventEmitter):
+class LocalSource(LocalStreamEndPoint):
     def __init__(self, protocol, seid, codec_capabilities, packet_pump):
         capabilities = [
             ServiceCapabilities(AVDTP_MEDIA_TRANSPORT_SERVICE_CATEGORY),
             codec_capabilities,
         ]
-        LocalStreamEndPoint.__init__(
-            self,
+        super().__init__(
             protocol,
             seid,
             codec_capabilities.media_type,
@@ -2029,14 +2056,13 @@
             capabilities,
             capabilities,
         )
-        EventEmitter.__init__(self)
         self.packet_pump = packet_pump
 
     async def start(self):
         if self.packet_pump:
             return await self.packet_pump.start(self.stream.rtp_channel)
 
-        self.emit('start', self.stream.rtp_channel)
+        self.emit('start')
 
     async def stop(self):
         if self.packet_pump:
@@ -2044,11 +2070,6 @@
 
         self.emit('stop')
 
-    def on_set_configuration_command(self, configuration):
-        # For now, blindly accept the configuration
-        logger.debug(f'<<< received source configuration: {configuration}')
-        self.configuration = configuration
-
     def on_start_command(self):
         asyncio.create_task(self.start())
 
@@ -2057,30 +2078,28 @@
 
 
 # -----------------------------------------------------------------------------
-class LocalSink(LocalStreamEndPoint, EventEmitter):
+class LocalSink(LocalStreamEndPoint):
     def __init__(self, protocol, seid, codec_capabilities):
         capabilities = [
             ServiceCapabilities(AVDTP_MEDIA_TRANSPORT_SERVICE_CATEGORY),
             codec_capabilities,
         ]
-        LocalStreamEndPoint.__init__(
-            self,
+        super().__init__(
             protocol,
             seid,
             codec_capabilities.media_type,
             AVDTP_TSEP_SNK,
             capabilities,
         )
-        EventEmitter.__init__(self)
-
-    def on_set_configuration_command(self, configuration):
-        # For now, blindly accept the configuration
-        logger.debug(f'<<< received sink configuration: {configuration}')
-        self.configuration = configuration
 
     def on_rtp_channel_open(self):
         logger.debug(color('<<< RTP channel open', 'magenta'))
         self.stream.rtp_channel.sink = self.on_avdtp_packet
+        super().on_rtp_channel_open()
+
+    def on_rtp_channel_close(self):
+        logger.debug(color('<<< RTP channel close', 'magenta'))
+        super().on_rtp_channel_close()
 
     def on_avdtp_packet(self, packet):
         rtp_packet = MediaPacket.from_bytes(packet)
diff --git a/bumble/codecs.py b/bumble/codecs.py
new file mode 100644
index 0000000..1d7ae82
--- /dev/null
+++ b/bumble/codecs.py
@@ -0,0 +1,381 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+from __future__ import annotations
+from dataclasses import dataclass
+
+
+# -----------------------------------------------------------------------------
+class BitReader:
+    """Simple but not optimized bit stream reader."""
+
+    data: bytes
+    bytes_position: int
+    bit_position: int
+    cache: int
+    bits_cached: int
+
+    def __init__(self, data: bytes):
+        self.data = data
+        self.byte_position = 0
+        self.bit_position = 0
+        self.cache = 0
+        self.bits_cached = 0
+
+    def read(self, bits: int) -> int:
+        """ "Read up to 32 bits."""
+
+        if bits > 32:
+            raise ValueError('maximum read size is 32')
+
+        if self.bits_cached >= bits:
+            # We have enough bits.
+            self.bits_cached -= bits
+            self.bit_position += bits
+            return (self.cache >> self.bits_cached) & ((1 << bits) - 1)
+
+        # Read more cache, up to 32 bits
+        feed_bytes = self.data[self.byte_position : self.byte_position + 4]
+        feed_size = len(feed_bytes)
+        feed_int = int.from_bytes(feed_bytes, byteorder='big')
+        if 8 * feed_size + self.bits_cached < bits:
+            raise ValueError('trying to read past the data')
+        self.byte_position += feed_size
+
+        # Combine the new cache and the old cache
+        cache = self.cache & ((1 << self.bits_cached) - 1)
+        new_bits = bits - self.bits_cached
+        self.bits_cached = 8 * feed_size - new_bits
+        result = (feed_int >> self.bits_cached) | (cache << new_bits)
+        self.cache = feed_int
+
+        self.bit_position += bits
+        return result
+
+    def read_bytes(self, count: int):
+        if self.bit_position + 8 * count > 8 * len(self.data):
+            raise ValueError('not enough data')
+
+        if self.bit_position % 8:
+            # Not byte aligned
+            result = bytearray(count)
+            for i in range(count):
+                result[i] = self.read(8)
+            return bytes(result)
+
+        # Byte aligned
+        self.byte_position = self.bit_position // 8
+        self.bits_cached = 0
+        self.cache = 0
+        offset = self.bit_position // 8
+        self.bit_position += 8 * count
+        return self.data[offset : offset + count]
+
+    def bits_left(self) -> int:
+        return (8 * len(self.data)) - self.bit_position
+
+    def skip(self, bits: int) -> None:
+        # Slow, but simple...
+        while bits:
+            if bits > 32:
+                self.read(32)
+                bits -= 32
+            else:
+                self.read(bits)
+                break
+
+
+# -----------------------------------------------------------------------------
+class AacAudioRtpPacket:
+    """AAC payload encapsulated in an RTP packet payload"""
+
+    @staticmethod
+    def latm_value(reader: BitReader) -> int:
+        bytes_for_value = reader.read(2)
+        value = 0
+        for _ in range(bytes_for_value + 1):
+            value = value * 256 + reader.read(8)
+        return value
+
+    @staticmethod
+    def program_config_element(reader: BitReader):
+        raise ValueError('program_config_element not supported')
+
+    @dataclass
+    class GASpecificConfig:
+        def __init__(
+            self, reader: BitReader, channel_configuration: int, audio_object_type: int
+        ) -> None:
+            # GASpecificConfig - ISO/EIC 14496-3 Table 4.1
+            frame_length_flag = reader.read(1)
+            depends_on_core_coder = reader.read(1)
+            if depends_on_core_coder:
+                self.core_coder_delay = reader.read(14)
+            extension_flag = reader.read(1)
+            if not channel_configuration:
+                AacAudioRtpPacket.program_config_element(reader)
+            if audio_object_type in (6, 20):
+                self.layer_nr = reader.read(3)
+            if extension_flag:
+                if audio_object_type == 22:
+                    num_of_sub_frame = reader.read(5)
+                layer_length = reader.read(11)
+                if audio_object_type in (17, 19, 20, 23):
+                    aac_section_data_resilience_flags = reader.read(1)
+                    aac_scale_factor_data_resilience_flags = reader.read(1)
+                    aac_spectral_data_resilience_flags = reader.read(1)
+                extension_flag_3 = reader.read(1)
+                if extension_flag_3 == 1:
+                    raise ValueError('extensionFlag3 == 1 not supported')
+
+    @staticmethod
+    def audio_object_type(reader: BitReader):
+        # GetAudioObjectType - ISO/EIC 14496-3 Table 1.16
+        audio_object_type = reader.read(5)
+        if audio_object_type == 31:
+            audio_object_type = 32 + reader.read(6)
+
+        return audio_object_type
+
+    @dataclass
+    class AudioSpecificConfig:
+        audio_object_type: int
+        sampling_frequency_index: int
+        sampling_frequency: int
+        channel_configuration: int
+        sbr_present_flag: int
+        ps_present_flag: int
+        extension_audio_object_type: int
+        extension_sampling_frequency_index: int
+        extension_sampling_frequency: int
+        extension_channel_configuration: int
+
+        SAMPLING_FREQUENCIES = [
+            96000,
+            88200,
+            64000,
+            48000,
+            44100,
+            32000,
+            24000,
+            22050,
+            16000,
+            12000,
+            11025,
+            8000,
+            7350,
+        ]
+
+        def __init__(self, reader: BitReader) -> None:
+            # AudioSpecificConfig - ISO/EIC 14496-3 Table 1.15
+            self.audio_object_type = AacAudioRtpPacket.audio_object_type(reader)
+            self.sampling_frequency_index = reader.read(4)
+            if self.sampling_frequency_index == 0xF:
+                self.sampling_frequency = reader.read(24)
+            else:
+                self.sampling_frequency = self.SAMPLING_FREQUENCIES[
+                    self.sampling_frequency_index
+                ]
+            self.channel_configuration = reader.read(4)
+            self.sbr_present_flag = -1
+            self.ps_present_flag = -1
+            if self.audio_object_type in (5, 29):
+                self.extension_audio_object_type = 5
+                self.sbc_present_flag = 1
+                if self.audio_object_type == 29:
+                    self.ps_present_flag = 1
+                self.extension_sampling_frequency_index = reader.read(4)
+                if self.extension_sampling_frequency_index == 0xF:
+                    self.extension_sampling_frequency = reader.read(24)
+                else:
+                    self.extension_sampling_frequency = self.SAMPLING_FREQUENCIES[
+                        self.extension_sampling_frequency_index
+                    ]
+                self.audio_object_type = AacAudioRtpPacket.audio_object_type(reader)
+                if self.audio_object_type == 22:
+                    self.extension_channel_configuration = reader.read(4)
+            else:
+                self.extension_audio_object_type = 0
+
+            if self.audio_object_type in (1, 2, 3, 4, 6, 7, 17, 19, 20, 21, 22, 23):
+                ga_specific_config = AacAudioRtpPacket.GASpecificConfig(
+                    reader, self.channel_configuration, self.audio_object_type
+                )
+            else:
+                raise ValueError(
+                    f'audioObjectType {self.audio_object_type} not supported'
+                )
+
+            # if self.extension_audio_object_type != 5 and bits_to_decode >= 16:
+            #     sync_extension_type = reader.read(11)
+            #     if sync_extension_type == 0x2B7:
+            #         self.extension_audio_object_type = AacAudioRtpPacket.audio_object_type(reader)
+            #         if self.extension_audio_object_type == 5:
+            #             self.sbr_present_flag = reader.read(1)
+            #             if self.sbr_present_flag:
+            #                 self.extension_sampling_frequency_index = reader.read(4)
+            #                 if self.extension_sampling_frequency_index == 0xF:
+            #                     self.extension_sampling_frequency = reader.read(24)
+            #                 else:
+            #                     self.extension_sampling_frequency = self.SAMPLING_FREQUENCIES[self.extension_sampling_frequency_index]
+            #                 if bits_to_decode >= 12:
+            #                     sync_extension_type = reader.read(11)
+            #                     if sync_extension_type == 0x548:
+            #                         self.ps_present_flag = reader.read(1)
+            #         elif self.extension_audio_object_type == 22:
+            #             self.sbr_present_flag = reader.read(1)
+            #             if self.sbr_present_flag:
+            #                 self.extension_sampling_frequency_index = reader.read(4)
+            #                 if self.extension_sampling_frequency_index == 0xF:
+            #                     self.extension_sampling_frequency = reader.read(24)
+            #                 else:
+            #                     self.extension_sampling_frequency = self.SAMPLING_FREQUENCIES[self.extension_sampling_frequency_index]
+            #             self.extension_channel_configuration = reader.read(4)
+
+    @dataclass
+    class StreamMuxConfig:
+        other_data_present: int
+        other_data_len_bits: int
+        audio_specific_config: AacAudioRtpPacket.AudioSpecificConfig
+
+        def __init__(self, reader: BitReader) -> None:
+            # StreamMuxConfig - ISO/EIC 14496-3 Table 1.42
+            audio_mux_version = reader.read(1)
+            if audio_mux_version == 1:
+                audio_mux_version_a = reader.read(1)
+            else:
+                audio_mux_version_a = 0
+            if audio_mux_version_a != 0:
+                raise ValueError('audioMuxVersionA != 0 not supported')
+            if audio_mux_version == 1:
+                tara_buffer_fullness = AacAudioRtpPacket.latm_value(reader)
+            stream_cnt = 0
+            all_streams_same_time_framing = reader.read(1)
+            num_sub_frames = reader.read(6)
+            num_program = reader.read(4)
+            if num_program != 0:
+                raise ValueError('num_program != 0 not supported')
+            num_layer = reader.read(3)
+            if num_layer != 0:
+                raise ValueError('num_layer != 0 not supported')
+            if audio_mux_version == 0:
+                self.audio_specific_config = AacAudioRtpPacket.AudioSpecificConfig(
+                    reader
+                )
+            else:
+                asc_len = AacAudioRtpPacket.latm_value(reader)
+                marker = reader.bit_position
+                self.audio_specific_config = AacAudioRtpPacket.AudioSpecificConfig(
+                    reader
+                )
+                audio_specific_config_len = reader.bit_position - marker
+                if asc_len < audio_specific_config_len:
+                    raise ValueError('audio_specific_config_len > asc_len')
+                asc_len -= audio_specific_config_len
+                reader.skip(asc_len)
+            frame_length_type = reader.read(3)
+            if frame_length_type == 0:
+                latm_buffer_fullness = reader.read(8)
+            elif frame_length_type == 1:
+                frame_length = reader.read(9)
+            else:
+                raise ValueError(f'frame_length_type {frame_length_type} not supported')
+
+            self.other_data_present = reader.read(1)
+            if self.other_data_present:
+                if audio_mux_version == 1:
+                    self.other_data_len_bits = AacAudioRtpPacket.latm_value(reader)
+                else:
+                    self.other_data_len_bits = 0
+                    while True:
+                        self.other_data_len_bits *= 256
+                        other_data_len_esc = reader.read(1)
+                        self.other_data_len_bits += reader.read(8)
+                        if other_data_len_esc == 0:
+                            break
+            crc_check_present = reader.read(1)
+            if crc_check_present:
+                crc_checksum = reader.read(8)
+
+    @dataclass
+    class AudioMuxElement:
+        payload: bytes
+        stream_mux_config: AacAudioRtpPacket.StreamMuxConfig
+
+        def __init__(self, reader: BitReader, mux_config_present: int):
+            if mux_config_present == 0:
+                raise ValueError('muxConfigPresent == 0 not supported')
+
+            # AudioMuxElement - ISO/EIC 14496-3 Table 1.41
+            use_same_stream_mux = reader.read(1)
+            if use_same_stream_mux:
+                raise ValueError('useSameStreamMux == 1 not supported')
+            self.stream_mux_config = AacAudioRtpPacket.StreamMuxConfig(reader)
+
+            # We only support:
+            # allStreamsSameTimeFraming == 1
+            # audioMuxVersionA == 0,
+            # numProgram == 0
+            # numSubFrames == 0
+            # numLayer == 0
+
+            mux_slot_length_bytes = 0
+            while True:
+                tmp = reader.read(8)
+                mux_slot_length_bytes += tmp
+                if tmp != 255:
+                    break
+
+            self.payload = reader.read_bytes(mux_slot_length_bytes)
+
+            if self.stream_mux_config.other_data_present:
+                reader.skip(self.stream_mux_config.other_data_len_bits)
+
+            # ByteAlign
+            while reader.bit_position % 8:
+                reader.read(1)
+
+    def __init__(self, data: bytes) -> None:
+        # Parse the bit stream
+        reader = BitReader(data)
+        self.audio_mux_element = self.AudioMuxElement(reader, mux_config_present=1)
+
+    def to_adts(self):
+        # pylint: disable=line-too-long
+        sampling_frequency_index = (
+            self.audio_mux_element.stream_mux_config.audio_specific_config.sampling_frequency_index
+        )
+        channel_configuration = (
+            self.audio_mux_element.stream_mux_config.audio_specific_config.channel_configuration
+        )
+        frame_size = len(self.audio_mux_element.payload)
+        return (
+            bytes(
+                [
+                    0xFF,
+                    0xF1,  # 0xF9 (MPEG2)
+                    0x40
+                    | (sampling_frequency_index << 2)
+                    | (channel_configuration >> 2),
+                    ((channel_configuration & 0x3) << 6) | ((frame_size + 7) >> 11),
+                    ((frame_size + 7) >> 3) & 0xFF,
+                    (((frame_size + 7) << 5) & 0xFF) | 0x1F,
+                    0xFC,
+                ]
+            )
+            + self.audio_mux_element.payload
+        )
diff --git a/bumble/controller.py b/bumble/controller.py
index cd7de3d..688fcd7 100644
--- a/bumble/controller.py
+++ b/bumble/controller.py
@@ -654,7 +654,7 @@
 
     def on_hci_create_connection_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.1.5 Create Connection command
+        See Bluetooth spec Vol 4, Part E - 7.1.5 Create Connection command
         '''
 
         if self.link is None:
@@ -685,7 +685,7 @@
 
     def on_hci_disconnect_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.1.6 Disconnect Command
+        See Bluetooth spec Vol 4, Part E - 7.1.6 Disconnect Command
         '''
         # First, say that the disconnection is pending
         self.send_hci_packet(
@@ -719,7 +719,7 @@
 
     def on_hci_accept_connection_request_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.1.8 Accept Connection Request command
+        See Bluetooth spec Vol 4, Part E - 7.1.8 Accept Connection Request command
         '''
 
         if self.link is None:
@@ -735,7 +735,7 @@
 
     def on_hci_switch_role_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.2.8 Switch Role command
+        See Bluetooth spec Vol 4, Part E - 7.2.8 Switch Role command
         '''
 
         if self.link is None:
@@ -751,21 +751,21 @@
 
     def on_hci_set_event_mask_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.1 Set Event Mask Command
+        See Bluetooth spec Vol 4, Part E - 7.3.1 Set Event Mask Command
         '''
         self.event_mask = command.event_mask
         return bytes([HCI_SUCCESS])
 
     def on_hci_reset_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.2 Reset Command
+        See Bluetooth spec Vol 4, Part E - 7.3.2 Reset Command
         '''
         # TODO: cleanup what needs to be reset
         return bytes([HCI_SUCCESS])
 
     def on_hci_write_local_name_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.11 Write Local Name Command
+        See Bluetooth spec Vol 4, Part E - 7.3.11 Write Local Name Command
         '''
         local_name = command.local_name
         if len(local_name):
@@ -780,7 +780,7 @@
 
     def on_hci_read_local_name_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.12 Read Local Name Command
+        See Bluetooth spec Vol 4, Part E - 7.3.12 Read Local Name Command
         '''
         local_name = bytes(self.local_name, 'utf-8')[:248]
         if len(local_name) < 248:
@@ -790,19 +790,19 @@
 
     def on_hci_read_class_of_device_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.25 Read Class of Device Command
+        See Bluetooth spec Vol 4, Part E - 7.3.25 Read Class of Device Command
         '''
         return bytes([HCI_SUCCESS, 0, 0, 0])
 
     def on_hci_write_class_of_device_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.26 Write Class of Device Command
+        See Bluetooth spec Vol 4, Part E - 7.3.26 Write Class of Device Command
         '''
         return bytes([HCI_SUCCESS])
 
     def on_hci_read_synchronous_flow_control_enable_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.36 Read Synchronous Flow Control Enable
+        See Bluetooth spec Vol 4, Part E - 7.3.36 Read Synchronous Flow Control Enable
         Command
         '''
         if self.sync_flow_control:
@@ -813,7 +813,7 @@
 
     def on_hci_write_synchronous_flow_control_enable_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.37 Write Synchronous Flow Control Enable
+        See Bluetooth spec Vol 4, Part E - 7.3.37 Write Synchronous Flow Control Enable
         Command
         '''
         ret = HCI_SUCCESS
@@ -825,41 +825,59 @@
             ret = HCI_INVALID_HCI_COMMAND_PARAMETERS_ERROR
         return bytes([ret])
 
+    def on_hci_set_controller_to_host_flow_control_command(self, _command):
+        '''
+        See Bluetooth spec Vol 4, Part E - 7.3.38 Set Controller To Host Flow Control
+        Command
+        '''
+        # For now we just accept the command but ignore the values.
+        # TODO: respect the passed in values.
+        return bytes([HCI_SUCCESS])
+
+    def on_hci_host_buffer_size_command(self, _command):
+        '''
+        See Bluetooth spec Vol 4, Part E - 7.3.39 Host Buffer Size Command
+        '''
+        # For now we just accept the command but ignore the values.
+        # TODO: respect the passed in values.
+        return bytes([HCI_SUCCESS])
+
     def on_hci_write_extended_inquiry_response_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.59 Write Simple Pairing Mode Command
+        See Bluetooth spec Vol 4, Part E - 7.3.56 Write Extended Inquiry Response
+        Command
         '''
         return bytes([HCI_SUCCESS])
 
     def on_hci_write_simple_pairing_mode_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.59 Write Simple Pairing Mode Command
+        See Bluetooth spec Vol 4, Part E - 7.3.59 Write Simple Pairing Mode Command
         '''
         return bytes([HCI_SUCCESS])
 
     def on_hci_set_event_mask_page_2_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.69 Set Event Mask Page 2 Command
+        See Bluetooth spec Vol 4, Part E - 7.3.69 Set Event Mask Page 2 Command
         '''
         self.event_mask_page_2 = command.event_mask_page_2
         return bytes([HCI_SUCCESS])
 
     def on_hci_read_le_host_support_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.78 Write LE Host Support Command
+        See Bluetooth spec Vol 4, Part E - 7.3.78 Write LE Host Support Command
         '''
         return bytes([HCI_SUCCESS, 1, 0])
 
     def on_hci_write_le_host_support_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.79 Write LE Host Support Command
+        See Bluetooth spec Vol 4, Part E - 7.3.79 Write LE Host Support Command
         '''
         # TODO / Just ignore for now
         return bytes([HCI_SUCCESS])
 
     def on_hci_write_authenticated_payload_timeout_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.3.94 Write Authenticated Payload Timeout
+        See Bluetooth spec Vol 4, Part E - 7.3.94 Write Authenticated Payload Timeout
         Command
         '''
         # TODO
@@ -867,7 +885,7 @@
 
     def on_hci_read_local_version_information_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.4.1 Read Local Version Information Command
+        See Bluetooth spec Vol 4, Part E - 7.4.1 Read Local Version Information Command
         '''
         return struct.pack(
             '<BBHBHH',
@@ -881,19 +899,19 @@
 
     def on_hci_read_local_supported_commands_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.4.2 Read Local Supported Commands Command
+        See Bluetooth spec Vol 4, Part E - 7.4.2 Read Local Supported Commands Command
         '''
         return bytes([HCI_SUCCESS]) + self.supported_commands
 
     def on_hci_read_local_supported_features_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.4.3 Read Local Supported Features Command
+        See Bluetooth spec Vol 4, Part E - 7.4.3 Read Local Supported Features Command
         '''
         return bytes([HCI_SUCCESS]) + self.lmp_features
 
     def on_hci_read_bd_addr_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.4.6 Read BD_ADDR Command
+        See Bluetooth spec Vol 4, Part E - 7.4.6 Read BD_ADDR Command
         '''
         bd_addr = (
             self._public_address.to_bytes()
@@ -904,14 +922,14 @@
 
     def on_hci_le_set_event_mask_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.1 LE Set Event Mask Command
+        See Bluetooth spec Vol 4, Part E - 7.8.1 LE Set Event Mask Command
         '''
         self.le_event_mask = command.le_event_mask
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_read_buffer_size_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.2 LE Read Buffer Size Command
+        See Bluetooth spec Vol 4, Part E - 7.8.2 LE Read Buffer Size Command
         '''
         return struct.pack(
             '<BHB',
@@ -922,49 +940,49 @@
 
     def on_hci_le_read_local_supported_features_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.3 LE Read Local Supported Features
+        See Bluetooth spec Vol 4, Part E - 7.8.3 LE Read Local Supported Features
         Command
         '''
         return bytes([HCI_SUCCESS]) + self.le_features
 
     def on_hci_le_set_random_address_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.4 LE Set Random Address Command
+        See Bluetooth spec Vol 4, Part E - 7.8.4 LE Set Random Address Command
         '''
         self.random_address = command.random_address
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_set_advertising_parameters_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.5 LE Set Advertising Parameters Command
+        See Bluetooth spec Vol 4, Part E - 7.8.5 LE Set Advertising Parameters Command
         '''
         self.advertising_parameters = command
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_read_advertising_physical_channel_tx_power_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.6 LE Read Advertising Physical Channel
+        See Bluetooth spec Vol 4, Part E - 7.8.6 LE Read Advertising Physical Channel
         Tx Power Command
         '''
         return bytes([HCI_SUCCESS, self.advertising_channel_tx_power])
 
     def on_hci_le_set_advertising_data_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.7 LE Set Advertising Data Command
+        See Bluetooth spec Vol 4, Part E - 7.8.7 LE Set Advertising Data Command
         '''
         self.advertising_data = command.advertising_data
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_set_scan_response_data_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.8 LE Set Scan Response Data Command
+        See Bluetooth spec Vol 4, Part E - 7.8.8 LE Set Scan Response Data Command
         '''
         self.le_scan_response_data = command.scan_response_data
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_set_advertising_enable_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.9 LE Set Advertising Enable Command
+        See Bluetooth spec Vol 4, Part E - 7.8.9 LE Set Advertising Enable Command
         '''
         if command.advertising_enable:
             self.start_advertising()
@@ -975,7 +993,7 @@
 
     def on_hci_le_set_scan_parameters_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.10 LE Set Scan Parameters Command
+        See Bluetooth spec Vol 4, Part E - 7.8.10 LE Set Scan Parameters Command
         '''
         self.le_scan_type = command.le_scan_type
         self.le_scan_interval = command.le_scan_interval
@@ -986,7 +1004,7 @@
 
     def on_hci_le_set_scan_enable_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.11 LE Set Scan Enable Command
+        See Bluetooth spec Vol 4, Part E - 7.8.11 LE Set Scan Enable Command
         '''
         self.le_scan_enable = command.le_scan_enable
         self.filter_duplicates = command.filter_duplicates
@@ -994,7 +1012,7 @@
 
     def on_hci_le_create_connection_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.12 LE Create Connection Command
+        See Bluetooth spec Vol 4, Part E - 7.8.12 LE Create Connection Command
         '''
 
         if not self.link:
@@ -1027,40 +1045,40 @@
 
     def on_hci_le_create_connection_cancel_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.13 LE Create Connection Cancel Command
+        See Bluetooth spec Vol 4, Part E - 7.8.13 LE Create Connection Cancel Command
         '''
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_read_filter_accept_list_size_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.14 LE Read Filter Accept List Size
+        See Bluetooth spec Vol 4, Part E - 7.8.14 LE Read Filter Accept List Size
         Command
         '''
         return bytes([HCI_SUCCESS, self.filter_accept_list_size])
 
     def on_hci_le_clear_filter_accept_list_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.15 LE Clear Filter Accept List Command
+        See Bluetooth spec Vol 4, Part E - 7.8.15 LE Clear Filter Accept List Command
         '''
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_add_device_to_filter_accept_list_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.16 LE Add Device To Filter Accept List
+        See Bluetooth spec Vol 4, Part E - 7.8.16 LE Add Device To Filter Accept List
         Command
         '''
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_remove_device_from_filter_accept_list_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.17 LE Remove Device From Filter Accept
+        See Bluetooth spec Vol 4, Part E - 7.8.17 LE Remove Device From Filter Accept
         List Command
         '''
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_read_remote_features_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.21 LE Read Remote Features Command
+        See Bluetooth spec Vol 4, Part E - 7.8.21 LE Read Remote Features Command
         '''
 
         # First, say that the command is pending
@@ -1083,13 +1101,13 @@
 
     def on_hci_le_rand_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.23 LE Rand Command
+        See Bluetooth spec Vol 4, Part E - 7.8.23 LE Rand Command
         '''
         return bytes([HCI_SUCCESS]) + struct.pack('Q', random.randint(0, 1 << 64))
 
     def on_hci_le_enable_encryption_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.24 LE Enable Encryption Command
+        See Bluetooth spec Vol 4, Part E - 7.8.24 LE Enable Encryption Command
         '''
 
         # Check the parameters
@@ -1122,13 +1140,13 @@
 
     def on_hci_le_read_supported_states_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.27 LE Read Supported States Command
+        See Bluetooth spec Vol 4, Part E - 7.8.27 LE Read Supported States Command
         '''
         return bytes([HCI_SUCCESS]) + self.le_states
 
     def on_hci_le_read_suggested_default_data_length_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.34 LE Read Suggested Default Data Length
+        See Bluetooth spec Vol 4, Part E - 7.8.34 LE Read Suggested Default Data Length
         Command
         '''
         return struct.pack(
@@ -1140,7 +1158,7 @@
 
     def on_hci_le_write_suggested_default_data_length_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.35 LE Write Suggested Default Data Length
+        See Bluetooth spec Vol 4, Part E - 7.8.35 LE Write Suggested Default Data Length
         Command
         '''
         self.suggested_max_tx_octets, self.suggested_max_tx_time = struct.unpack(
@@ -1150,33 +1168,33 @@
 
     def on_hci_le_read_local_p_256_public_key_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.36 LE Read P-256 Public Key Command
+        See Bluetooth spec Vol 4, Part E - 7.8.36 LE Read P-256 Public Key Command
         '''
         # TODO create key and send HCI_LE_Read_Local_P-256_Public_Key_Complete event
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_add_device_to_resolving_list_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.38 LE Add Device To Resolving List
+        See Bluetooth spec Vol 4, Part E - 7.8.38 LE Add Device To Resolving List
         Command
         '''
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_clear_resolving_list_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.40 LE Clear Resolving List Command
+        See Bluetooth spec Vol 4, Part E - 7.8.40 LE Clear Resolving List Command
         '''
         return bytes([HCI_SUCCESS])
 
     def on_hci_le_read_resolving_list_size_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.41 LE Read Resolving List Size Command
+        See Bluetooth spec Vol 4, Part E - 7.8.41 LE Read Resolving List Size Command
         '''
         return bytes([HCI_SUCCESS, self.resolving_list_size])
 
     def on_hci_le_set_address_resolution_enable_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.44 LE Set Address Resolution Enable
+        See Bluetooth spec Vol 4, Part E - 7.8.44 LE Set Address Resolution Enable
         Command
         '''
         ret = HCI_SUCCESS
@@ -1190,7 +1208,7 @@
 
     def on_hci_le_set_resolvable_private_address_timeout_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.45 LE Set Resolvable Private Address
+        See Bluetooth spec Vol 4, Part E - 7.8.45 LE Set Resolvable Private Address
         Timeout Command
         '''
         self.le_rpa_timeout = command.rpa_timeout
@@ -1198,7 +1216,7 @@
 
     def on_hci_le_read_maximum_data_length_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.46 LE Read Maximum Data Length Command
+        See Bluetooth spec Vol 4, Part E - 7.8.46 LE Read Maximum Data Length Command
         '''
         return struct.pack(
             '<BHHHH',
@@ -1211,7 +1229,7 @@
 
     def on_hci_le_read_phy_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.47 LE Read PHY Command
+        See Bluetooth spec Vol 4, Part E - 7.8.47 LE Read PHY Command
         '''
         return struct.pack(
             '<BHBB',
@@ -1223,7 +1241,7 @@
 
     def on_hci_le_set_default_phy_command(self, command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.48 LE Set Default PHY Command
+        See Bluetooth spec Vol 4, Part E - 7.8.48 LE Set Default PHY Command
         '''
         self.default_phy = {
             'all_phys': command.all_phys,
@@ -1234,6 +1252,6 @@
 
     def on_hci_le_read_transmit_power_command(self, _command):
         '''
-        See Bluetooth spec Vol 2, Part E - 7.8.74 LE Read Transmit Power Command
+        See Bluetooth spec Vol 4, Part E - 7.8.74 LE Read Transmit Power Command
         '''
         return struct.pack('<BBB', HCI_SUCCESS, 0, 0)
diff --git a/bumble/core.py b/bumble/core.py
index 1cc10ec..2e3f4af 100644
--- a/bumble/core.py
+++ b/bumble/core.py
@@ -17,7 +17,7 @@
 # -----------------------------------------------------------------------------
 from __future__ import annotations
 import struct
-from typing import List, Optional, Tuple, Union, cast
+from typing import List, Optional, Tuple, Union, cast, Dict
 
 from .company_ids import COMPANY_IDENTIFIERS
 
@@ -53,7 +53,7 @@
     return names
 
 
-def name_or_number(dictionary, number, width=2):
+def name_or_number(dictionary: Dict[int, str], number: int, width: int = 2) -> str:
     name = dictionary.get(number)
     if name is not None:
         return name
@@ -562,11 +562,82 @@
         PERIPHERAL_HANDHELD_GESTURAL_INPUT_DEVICE_MINOR_DEVICE_CLASS: 'Handheld gestural input device'
     }
 
+    WEARABLE_UNCATEGORIZED_MINOR_DEVICE_CLASS = 0x00
+    WEARABLE_WRISTWATCH_MINOR_DEVICE_CLASS    = 0x01
+    WEARABLE_PAGER_MINOR_DEVICE_CLASS         = 0x02
+    WEARABLE_JACKET_MINOR_DEVICE_CLASS        = 0x03
+    WEARABLE_HELMET_MINOR_DEVICE_CLASS        = 0x04
+    WEARABLE_GLASSES_MINOR_DEVICE_CLASS       = 0x05
+
+    WEARABLE_MINOR_DEVICE_CLASS_NAMES = {
+        WEARABLE_UNCATEGORIZED_MINOR_DEVICE_CLASS: 'Uncategorized',
+        WEARABLE_WRISTWATCH_MINOR_DEVICE_CLASS:    'Wristwatch',
+        WEARABLE_PAGER_MINOR_DEVICE_CLASS:         'Pager',
+        WEARABLE_JACKET_MINOR_DEVICE_CLASS:        'Jacket',
+        WEARABLE_HELMET_MINOR_DEVICE_CLASS:        'Helmet',
+        WEARABLE_GLASSES_MINOR_DEVICE_CLASS:       'Glasses',
+    }
+
+    TOY_UNCATEGORIZED_MINOR_DEVICE_CLASS      = 0x00
+    TOY_ROBOT_MINOR_DEVICE_CLASS              = 0x01
+    TOY_VEHICLE_MINOR_DEVICE_CLASS            = 0x02
+    TOY_DOLL_ACTION_FIGURE_MINOR_DEVICE_CLASS = 0x03
+    TOY_CONTROLLER_MINOR_DEVICE_CLASS         = 0x04
+    TOY_GAME_MINOR_DEVICE_CLASS               = 0x05
+
+    TOY_MINOR_DEVICE_CLASS_NAMES = {
+        TOY_UNCATEGORIZED_MINOR_DEVICE_CLASS:      'Uncategorized',
+        TOY_ROBOT_MINOR_DEVICE_CLASS:              'Robot',
+        TOY_VEHICLE_MINOR_DEVICE_CLASS:            'Vehicle',
+        TOY_DOLL_ACTION_FIGURE_MINOR_DEVICE_CLASS: 'Doll/Action figure',
+        TOY_CONTROLLER_MINOR_DEVICE_CLASS:         'Controller',
+        TOY_GAME_MINOR_DEVICE_CLASS:               'Game',
+    }
+
+    HEALTH_UNDEFINED_MINOR_DEVICE_CLASS                 = 0x00
+    HEALTH_BLOOD_PRESSURE_MONITOR_MINOR_DEVICE_CLASS    = 0x01
+    HEALTH_THERMOMETER_MINOR_DEVICE_CLASS               = 0x02
+    HEALTH_WEIGHING_SCALE_MINOR_DEVICE_CLASS            = 0x03
+    HEALTH_GLUCOSE_METER_MINOR_DEVICE_CLASS             = 0x04
+    HEALTH_PULSE_OXIMETER_MINOR_DEVICE_CLASS            = 0x05
+    HEALTH_HEART_PULSE_RATE_MONITOR_MINOR_DEVICE_CLASS  = 0x06
+    HEALTH_HEALTH_DATA_DISPLAY_MINOR_DEVICE_CLASS       = 0x07
+    HEALTH_STEP_COUNTER_MINOR_DEVICE_CLASS              = 0x08
+    HEALTH_BODY_COMPOSITION_ANALYZER_MINOR_DEVICE_CLASS = 0x09
+    HEALTH_PEAK_FLOW_MONITOR_MINOR_DEVICE_CLASS         = 0x0A
+    HEALTH_MEDICATION_MONITOR_MINOR_DEVICE_CLASS        = 0x0B
+    HEALTH_KNEE_PROSTHESIS_MINOR_DEVICE_CLASS           = 0x0C
+    HEALTH_ANKLE_PROSTHESIS_MINOR_DEVICE_CLASS          = 0x0D
+    HEALTH_GENERIC_HEALTH_MANAGER_MINOR_DEVICE_CLASS    = 0x0E
+    HEALTH_PERSONAL_MOBILITY_DEVICE_MINOR_DEVICE_CLASS  = 0x0F
+
+    HEALTH_MINOR_DEVICE_CLASS_NAMES = {
+        HEALTH_UNDEFINED_MINOR_DEVICE_CLASS:                 'Undefined',
+        HEALTH_BLOOD_PRESSURE_MONITOR_MINOR_DEVICE_CLASS:    'Blood Pressure Monitor',
+        HEALTH_THERMOMETER_MINOR_DEVICE_CLASS:               'Thermometer',
+        HEALTH_WEIGHING_SCALE_MINOR_DEVICE_CLASS:            'Weighing Scale',
+        HEALTH_GLUCOSE_METER_MINOR_DEVICE_CLASS:             'Glucose Meter',
+        HEALTH_PULSE_OXIMETER_MINOR_DEVICE_CLASS:            'Pulse Oximeter',
+        HEALTH_HEART_PULSE_RATE_MONITOR_MINOR_DEVICE_CLASS:  'Heart/Pulse Rate Monitor',
+        HEALTH_HEALTH_DATA_DISPLAY_MINOR_DEVICE_CLASS:       'Health Data Display',
+        HEALTH_STEP_COUNTER_MINOR_DEVICE_CLASS:              'Step Counter',
+        HEALTH_BODY_COMPOSITION_ANALYZER_MINOR_DEVICE_CLASS: 'Body Composition Analyzer',
+        HEALTH_PEAK_FLOW_MONITOR_MINOR_DEVICE_CLASS:         'Peak Flow Monitor',
+        HEALTH_MEDICATION_MONITOR_MINOR_DEVICE_CLASS:        'Medication Monitor',
+        HEALTH_KNEE_PROSTHESIS_MINOR_DEVICE_CLASS:           'Knee Prosthesis',
+        HEALTH_ANKLE_PROSTHESIS_MINOR_DEVICE_CLASS:          'Ankle Prosthesis',
+        HEALTH_GENERIC_HEALTH_MANAGER_MINOR_DEVICE_CLASS:    'Generic Health Manager',
+        HEALTH_PERSONAL_MOBILITY_DEVICE_MINOR_DEVICE_CLASS:  'Personal Mobility Device',
+    }
+
     MINOR_DEVICE_CLASS_NAMES = {
         COMPUTER_MAJOR_DEVICE_CLASS:    COMPUTER_MINOR_DEVICE_CLASS_NAMES,
         PHONE_MAJOR_DEVICE_CLASS:       PHONE_MINOR_DEVICE_CLASS_NAMES,
         AUDIO_VIDEO_MAJOR_DEVICE_CLASS: AUDIO_VIDEO_MINOR_DEVICE_CLASS_NAMES,
-        PERIPHERAL_MAJOR_DEVICE_CLASS:  PERIPHERAL_MINOR_DEVICE_CLASS_NAMES
+        PERIPHERAL_MAJOR_DEVICE_CLASS:  PERIPHERAL_MINOR_DEVICE_CLASS_NAMES,
+        WEARABLE_MAJOR_DEVICE_CLASS:    WEARABLE_MINOR_DEVICE_CLASS_NAMES,
+        TOY_MAJOR_DEVICE_CLASS:         TOY_MINOR_DEVICE_CLASS_NAMES,
+        HEALTH_MAJOR_DEVICE_CLASS:      HEALTH_MINOR_DEVICE_CLASS_NAMES,
     }
 
     # fmt: on
diff --git a/bumble/device.py b/bumble/device.py
index 258a43d..031c071 100644
--- a/bumble/device.py
+++ b/bumble/device.py
@@ -826,6 +826,12 @@
         advertising_data = config.get('advertising_data')
         if advertising_data:
             self.advertising_data = bytes.fromhex(advertising_data)
+        elif config.get('name') is not None:
+            self.advertising_data = bytes(
+                AdvertisingData(
+                    [(AdvertisingData.COMPLETE_LOCAL_NAME, bytes(self.name, 'utf-8'))]
+                )
+            )
 
     def load_from_file(self, filename):
         with open(filename, 'r', encoding='utf-8') as file:
@@ -949,11 +955,15 @@
         return cls(config=config)
 
     @classmethod
+    def from_config_with_hci(cls, config, hci_source, hci_sink):
+        host = Host(controller_source=hci_source, controller_sink=hci_sink)
+        return cls(config=config, host=host)
+
+    @classmethod
     def from_config_file_with_hci(cls, filename, hci_source, hci_sink):
         config = DeviceConfiguration()
         config.load_from_file(filename)
-        host = Host(controller_source=hci_source, controller_sink=hci_sink)
-        return cls(config=config, host=host)
+        return cls.from_config_with_hci(config, hci_source, hci_sink)
 
     def __init__(
         self,
@@ -2435,7 +2445,7 @@
 
             if result.status != HCI_COMMAND_STATUS_PENDING:
                 logger.warning(
-                    'HCI_Set_Connection_Encryption_Command failed: '
+                    'HCI_Remote_Name_Request_Command failed: '
                     f'{HCI_Constant.error_name(result.status)}'
                 )
                 raise HCI_StatusError(result)
@@ -2841,18 +2851,22 @@
         method = methods[peer_io_capability][io_capability]
 
         async def reply() -> None:
-            if await connection.abort_on('disconnection', method()):
-                await self.host.send_command(
-                    HCI_User_Confirmation_Request_Reply_Command(  # type: ignore[call-arg]
-                        bd_addr=connection.peer_address
+            try:
+                if await connection.abort_on('disconnection', method()):
+                    await self.host.send_command(
+                        HCI_User_Confirmation_Request_Reply_Command(  # type: ignore[call-arg]
+                            bd_addr=connection.peer_address
+                        )
                     )
+                    return
+            except Exception as error:
+                logger.warning(f'exception while confirming: {error}')
+
+            await self.host.send_command(
+                HCI_User_Confirmation_Request_Negative_Reply_Command(  # type: ignore[call-arg]
+                    bd_addr=connection.peer_address
                 )
-            else:
-                await self.host.send_command(
-                    HCI_User_Confirmation_Request_Negative_Reply_Command(  # type: ignore[call-arg]
-                        bd_addr=connection.peer_address
-                    )
-                )
+            )
 
         AsyncRunner.spawn(reply())
 
@@ -2864,21 +2878,25 @@
         pairing_config = self.pairing_config_factory(connection)
 
         async def reply() -> None:
-            number = await connection.abort_on(
-                'disconnection', pairing_config.delegate.get_number()
+            try:
+                number = await connection.abort_on(
+                    'disconnection', pairing_config.delegate.get_number()
+                )
+                if number is not None:
+                    await self.host.send_command(
+                        HCI_User_Passkey_Request_Reply_Command(  # type: ignore[call-arg]
+                            bd_addr=connection.peer_address, numeric_value=number
+                        )
+                    )
+                    return
+            except Exception as error:
+                logger.warning(f'exception while asking for pass-key: {error}')
+
+            await self.host.send_command(
+                HCI_User_Passkey_Request_Negative_Reply_Command(  # type: ignore[call-arg]
+                    bd_addr=connection.peer_address
+                )
             )
-            if number is not None:
-                await self.host.send_command(
-                    HCI_User_Passkey_Request_Reply_Command(  # type: ignore[call-arg]
-                        bd_addr=connection.peer_address, numeric_value=number
-                    )
-                )
-            else:
-                await self.host.send_command(
-                    HCI_User_Passkey_Request_Negative_Reply_Command(  # type: ignore[call-arg]
-                        bd_addr=connection.peer_address
-                    )
-                )
 
         AsyncRunner.spawn(reply())
 
@@ -3088,7 +3106,16 @@
     def on_pairing_start(self, connection: Connection) -> None:
         connection.emit('pairing_start')
 
-    def on_pairing(self, connection: Connection, keys: PairingKeys, sc: bool) -> None:
+    def on_pairing(
+        self,
+        connection: Connection,
+        identity_address: Optional[Address],
+        keys: PairingKeys,
+        sc: bool,
+    ) -> None:
+        if identity_address is not None:
+            connection.peer_resolvable_address = connection.peer_address
+            connection.peer_address = identity_address
         connection.sc = sc
         connection.authenticated = True
         connection.emit('pairing', keys)
diff --git a/bumble/drivers/__init__.py b/bumble/drivers/__init__.py
new file mode 100644
index 0000000..2decab7
--- /dev/null
+++ b/bumble/drivers/__init__.py
@@ -0,0 +1,68 @@
+# Copyright 2021-2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+Drivers that can be used to customize the interaction between a host and a controller,
+like loading firmware after a cold start.
+"""
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+import abc
+import logging
+from . import rtk
+
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+
+# -----------------------------------------------------------------------------
+# Classes
+# -----------------------------------------------------------------------------
+class Driver(abc.ABC):
+    """Base class for drivers."""
+
+    @staticmethod
+    async def for_host(_host):
+        """Return a driver instance for a host.
+
+        Args:
+            host: Host object for which a driver should be created.
+
+        Returns:
+            A Driver instance if a driver should be instantiated for this host, or
+            None if no driver instance of this class is needed.
+        """
+        return None
+
+    @abc.abstractmethod
+    async def init_controller(self):
+        """Initialize the controller."""
+
+
+# -----------------------------------------------------------------------------
+# Functions
+# -----------------------------------------------------------------------------
+async def get_driver_for_host(host):
+    """Probe all known diver classes until one returns a valid instance for a host,
+    or none is found.
+    """
+    if driver := await rtk.Driver.for_host(host):
+        logger.debug("Instantiated RTK driver")
+        return driver
+
+    return None
diff --git a/bumble/drivers/rtk.py b/bumble/drivers/rtk.py
new file mode 100644
index 0000000..c0bccc9
--- /dev/null
+++ b/bumble/drivers/rtk.py
@@ -0,0 +1,647 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+Support for Realtek USB dongles.
+Based on various online bits of information, including the Linux kernel.
+(see `drivers/bluetooth/btrtl.c`)
+"""
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+from dataclasses import dataclass
+import asyncio
+import enum
+import logging
+import math
+import os
+import pathlib
+import platform
+import struct
+from typing import Tuple
+import weakref
+
+
+from bumble.hci import (
+    hci_command_op_code,
+    STATUS_SPEC,
+    HCI_SUCCESS,
+    HCI_COMMAND_NAMES,
+    HCI_Command,
+    HCI_Reset_Command,
+    HCI_Read_Local_Version_Information_Command,
+)
+
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+
+# -----------------------------------------------------------------------------
+# Constants
+# -----------------------------------------------------------------------------
+RTK_ROM_LMP_8723A = 0x1200
+RTK_ROM_LMP_8723B = 0x8723
+RTK_ROM_LMP_8821A = 0x8821
+RTK_ROM_LMP_8761A = 0x8761
+RTK_ROM_LMP_8822B = 0x8822
+RTK_ROM_LMP_8852A = 0x8852
+RTK_CONFIG_MAGIC = 0x8723AB55
+
+RTK_EPATCH_SIGNATURE = b"Realtech"
+
+RTK_FRAGMENT_LENGTH = 252
+
+RTK_FIRMWARE_DIR_ENV = "BUMBLE_RTK_FIRMWARE_DIR"
+RTK_LINUX_FIRMWARE_DIR = "/lib/firmware/rtl_bt"
+
+
+class RtlProjectId(enum.IntEnum):
+    PROJECT_ID_8723A = 0
+    PROJECT_ID_8723B = 1
+    PROJECT_ID_8821A = 2
+    PROJECT_ID_8761A = 3
+    PROJECT_ID_8822B = 8
+    PROJECT_ID_8723D = 9
+    PROJECT_ID_8821C = 10
+    PROJECT_ID_8822C = 13
+    PROJECT_ID_8761B = 14
+    PROJECT_ID_8852A = 18
+    PROJECT_ID_8852B = 20
+    PROJECT_ID_8852C = 25
+
+
+RTK_PROJECT_ID_TO_ROM = {
+    0: RTK_ROM_LMP_8723A,
+    1: RTK_ROM_LMP_8723B,
+    2: RTK_ROM_LMP_8821A,
+    3: RTK_ROM_LMP_8761A,
+    8: RTK_ROM_LMP_8822B,
+    9: RTK_ROM_LMP_8723B,
+    10: RTK_ROM_LMP_8821A,
+    13: RTK_ROM_LMP_8822B,
+    14: RTK_ROM_LMP_8761A,
+    18: RTK_ROM_LMP_8852A,
+    20: RTK_ROM_LMP_8852A,
+    25: RTK_ROM_LMP_8852A,
+}
+
+# List of USB (VendorID, ProductID) for Realtek-based devices.
+RTK_USB_PRODUCTS = {
+    # Realtek 8723AE
+    (0x0930, 0x021D),
+    (0x13D3, 0x3394),
+    # Realtek 8723BE
+    (0x0489, 0xE085),
+    (0x0489, 0xE08B),
+    (0x04F2, 0xB49F),
+    (0x13D3, 0x3410),
+    (0x13D3, 0x3416),
+    (0x13D3, 0x3459),
+    (0x13D3, 0x3494),
+    # Realtek 8723BU
+    (0x7392, 0xA611),
+    # Realtek 8723DE
+    (0x0BDA, 0xB009),
+    (0x2FF8, 0xB011),
+    # Realtek 8761BUV
+    (0x0B05, 0x190E),
+    (0x0BDA, 0x8771),
+    (0x2230, 0x0016),
+    (0x2357, 0x0604),
+    (0x2550, 0x8761),
+    (0x2B89, 0x8761),
+    (0x7392, 0xC611),
+    # Realtek 8821AE
+    (0x0B05, 0x17DC),
+    (0x13D3, 0x3414),
+    (0x13D3, 0x3458),
+    (0x13D3, 0x3461),
+    (0x13D3, 0x3462),
+    # Realtek 8821CE
+    (0x0BDA, 0xB00C),
+    (0x0BDA, 0xC822),
+    (0x13D3, 0x3529),
+    # Realtek 8822BE
+    (0x0B05, 0x185C),
+    (0x13D3, 0x3526),
+    # Realtek 8822CE
+    (0x04C5, 0x161F),
+    (0x04CA, 0x4005),
+    (0x0B05, 0x18EF),
+    (0x0BDA, 0xB00C),
+    (0x0BDA, 0xC123),
+    (0x0BDA, 0xC822),
+    (0x0CB5, 0xC547),
+    (0x1358, 0xC123),
+    (0x13D3, 0x3548),
+    (0x13D3, 0x3549),
+    (0x13D3, 0x3553),
+    (0x13D3, 0x3555),
+    (0x2FF8, 0x3051),
+    # Realtek 8822CU
+    (0x13D3, 0x3549),
+    # Realtek 8852AE
+    (0x04C5, 0x165C),
+    (0x04CA, 0x4006),
+    (0x0BDA, 0x2852),
+    (0x0BDA, 0x385A),
+    (0x0BDA, 0x4852),
+    (0x0BDA, 0xC852),
+    (0x0CB8, 0xC549),
+    # Realtek 8852BE
+    (0x0BDA, 0x887B),
+    (0x0CB8, 0xC559),
+    (0x13D3, 0x3571),
+    # Realtek 8852CE
+    (0x04C5, 0x1675),
+    (0x04CA, 0x4007),
+    (0x0CB8, 0xC558),
+    (0x13D3, 0x3586),
+    (0x13D3, 0x3587),
+    (0x13D3, 0x3592),
+}
+
+# -----------------------------------------------------------------------------
+# HCI Commands
+# -----------------------------------------------------------------------------
+HCI_RTK_READ_ROM_VERSION_COMMAND = hci_command_op_code(0x3F, 0x6D)
+HCI_COMMAND_NAMES[HCI_RTK_READ_ROM_VERSION_COMMAND] = "HCI_RTK_READ_ROM_VERSION_COMMAND"
+
+
+@HCI_Command.command(return_parameters_fields=[("status", STATUS_SPEC), ("version", 1)])
+class HCI_RTK_Read_ROM_Version_Command(HCI_Command):
+    pass
+
+
+HCI_RTK_DOWNLOAD_COMMAND = hci_command_op_code(0x3F, 0x20)
+HCI_COMMAND_NAMES[HCI_RTK_DOWNLOAD_COMMAND] = "HCI_RTK_DOWNLOAD_COMMAND"
+
+
+@HCI_Command.command(
+    fields=[("index", 1), ("payload", RTK_FRAGMENT_LENGTH)],
+    return_parameters_fields=[("status", STATUS_SPEC), ("index", 1)],
+)
+class HCI_RTK_Download_Command(HCI_Command):
+    pass
+
+
+HCI_RTK_DROP_FIRMWARE_COMMAND = hci_command_op_code(0x3F, 0x66)
+HCI_COMMAND_NAMES[HCI_RTK_DROP_FIRMWARE_COMMAND] = "HCI_RTK_DROP_FIRMWARE_COMMAND"
+
+
+@HCI_Command.command()
+class HCI_RTK_Drop_Firmware_Command(HCI_Command):
+    pass
+
+
+# -----------------------------------------------------------------------------
+class Firmware:
+    def __init__(self, firmware):
+        extension_sig = bytes([0x51, 0x04, 0xFD, 0x77])
+
+        if not firmware.startswith(RTK_EPATCH_SIGNATURE):
+            raise ValueError("Firmware does not start with epatch signature")
+
+        if not firmware.endswith(extension_sig):
+            raise ValueError("Firmware does not end with extension sig")
+
+        # The firmware should start with a 14 byte header.
+        epatch_header_size = 14
+        if len(firmware) < epatch_header_size:
+            raise ValueError("Firmware too short")
+
+        # Look for the "project ID", starting from the end.
+        offset = len(firmware) - len(extension_sig)
+        project_id = -1
+        while offset >= epatch_header_size:
+            length, opcode = firmware[offset - 2 : offset]
+            offset -= 2
+
+            if opcode == 0xFF:
+                # End
+                break
+
+            if length == 0:
+                raise ValueError("Invalid 0-length instruction")
+
+            if opcode == 0 and length == 1:
+                project_id = firmware[offset - 1]
+                break
+
+            offset -= length
+
+        if project_id < 0:
+            raise ValueError("Project ID not found")
+
+        self.project_id = project_id
+
+        # Read the patch tables info.
+        self.version, num_patches = struct.unpack("<IH", firmware[8:14])
+        self.patches = []
+
+        # The patches tables are laid out as:
+        # <ChipID_1><ChipID_2>...<ChipID_N>  (16 bits each)
+        # <PatchLength_1><PatchLength_2>...<PatchLength_N> (16 bits each)
+        # <PatchOffset_1><PatchOffset_2>...<PatchOffset_N> (32 bits each)
+        if epatch_header_size + 8 * num_patches > len(firmware):
+            raise ValueError("Firmware too short")
+        chip_id_table_offset = epatch_header_size
+        patch_length_table_offset = chip_id_table_offset + 2 * num_patches
+        patch_offset_table_offset = chip_id_table_offset + 4 * num_patches
+        for patch_index in range(num_patches):
+            chip_id_offset = chip_id_table_offset + 2 * patch_index
+            (chip_id,) = struct.unpack_from("<H", firmware, chip_id_offset)
+            (patch_length,) = struct.unpack_from(
+                "<H", firmware, patch_length_table_offset + 2 * patch_index
+            )
+            (patch_offset,) = struct.unpack_from(
+                "<I", firmware, patch_offset_table_offset + 4 * patch_index
+            )
+            if patch_offset + patch_length > len(firmware):
+                raise ValueError("Firmware too short")
+
+            # Get the SVN version for the patch
+            (svn_version,) = struct.unpack_from(
+                "<I", firmware, patch_offset + patch_length - 8
+            )
+
+            # Create a payload with the patch, replacing the last 4 bytes with
+            # the firmware version.
+            self.patches.append(
+                (
+                    chip_id,
+                    firmware[patch_offset : patch_offset + patch_length - 4]
+                    + struct.pack("<I", self.version),
+                    svn_version,
+                )
+            )
+
+
+class Driver:
+    @dataclass
+    class DriverInfo:
+        rom: int
+        hci: Tuple[int, int]
+        config_needed: bool
+        has_rom_version: bool
+        has_msft_ext: bool = False
+        fw_name: str = ""
+        config_name: str = ""
+
+    DRIVER_INFOS = [
+        # 8723A
+        DriverInfo(
+            rom=RTK_ROM_LMP_8723A,
+            hci=(0x0B, 0x06),
+            config_needed=False,
+            has_rom_version=False,
+            fw_name="rtl8723a_fw.bin",
+            config_name="",
+        ),
+        # 8723B
+        DriverInfo(
+            rom=RTK_ROM_LMP_8723B,
+            hci=(0x0B, 0x06),
+            config_needed=False,
+            has_rom_version=True,
+            fw_name="rtl8723b_fw.bin",
+            config_name="rtl8723b_config.bin",
+        ),
+        # 8723D
+        DriverInfo(
+            rom=RTK_ROM_LMP_8723B,
+            hci=(0x0D, 0x08),
+            config_needed=True,
+            has_rom_version=True,
+            fw_name="rtl8723d_fw.bin",
+            config_name="rtl8723d_config.bin",
+        ),
+        # 8821A
+        DriverInfo(
+            rom=RTK_ROM_LMP_8821A,
+            hci=(0x0A, 0x06),
+            config_needed=False,
+            has_rom_version=True,
+            fw_name="rtl8821a_fw.bin",
+            config_name="rtl8821a_config.bin",
+        ),
+        # 8821C
+        DriverInfo(
+            rom=RTK_ROM_LMP_8821A,
+            hci=(0x0C, 0x08),
+            config_needed=False,
+            has_rom_version=True,
+            has_msft_ext=True,
+            fw_name="rtl8821c_fw.bin",
+            config_name="rtl8821c_config.bin",
+        ),
+        # 8761A
+        DriverInfo(
+            rom=RTK_ROM_LMP_8761A,
+            hci=(0x0A, 0x06),
+            config_needed=False,
+            has_rom_version=True,
+            fw_name="rtl8761a_fw.bin",
+            config_name="rtl8761a_config.bin",
+        ),
+        # 8761BU
+        DriverInfo(
+            rom=RTK_ROM_LMP_8761A,
+            hci=(0x0B, 0x0A),
+            config_needed=False,
+            has_rom_version=True,
+            fw_name="rtl8761bu_fw.bin",
+            config_name="rtl8761bu_config.bin",
+        ),
+        # 8822C
+        DriverInfo(
+            rom=RTK_ROM_LMP_8822B,
+            hci=(0x0C, 0x0A),
+            config_needed=False,
+            has_rom_version=True,
+            has_msft_ext=True,
+            fw_name="rtl8822cu_fw.bin",
+            config_name="rtl8822cu_config.bin",
+        ),
+        # 8822B
+        DriverInfo(
+            rom=RTK_ROM_LMP_8822B,
+            hci=(0x0B, 0x07),
+            config_needed=True,
+            has_rom_version=True,
+            has_msft_ext=True,
+            fw_name="rtl8822b_fw.bin",
+            config_name="rtl8822b_config.bin",
+        ),
+        # 8852A
+        DriverInfo(
+            rom=RTK_ROM_LMP_8852A,
+            hci=(0x0A, 0x0B),
+            config_needed=False,
+            has_rom_version=True,
+            has_msft_ext=True,
+            fw_name="rtl8852au_fw.bin",
+            config_name="rtl8852au_config.bin",
+        ),
+        # 8852B
+        DriverInfo(
+            rom=RTK_ROM_LMP_8852A,
+            hci=(0xB, 0xB),
+            config_needed=False,
+            has_rom_version=True,
+            has_msft_ext=True,
+            fw_name="rtl8852bu_fw.bin",
+            config_name="rtl8852bu_config.bin",
+        ),
+        # 8852C
+        DriverInfo(
+            rom=RTK_ROM_LMP_8852A,
+            hci=(0x0C, 0x0C),
+            config_needed=False,
+            has_rom_version=True,
+            has_msft_ext=True,
+            fw_name="rtl8852cu_fw.bin",
+            config_name="rtl8852cu_config.bin",
+        ),
+    ]
+
+    POST_DROP_DELAY = 0.2
+
+    @staticmethod
+    def find_driver_info(hci_version, hci_subversion, lmp_subversion):
+        for driver_info in Driver.DRIVER_INFOS:
+            if driver_info.rom == lmp_subversion and driver_info.hci == (
+                hci_subversion,
+                hci_version,
+            ):
+                return driver_info
+
+        return None
+
+    @staticmethod
+    def find_binary_path(file_name):
+        # First check if an environment variable is set
+        if RTK_FIRMWARE_DIR_ENV in os.environ:
+            if (
+                path := pathlib.Path(os.environ[RTK_FIRMWARE_DIR_ENV]) / file_name
+            ).is_file():
+                logger.debug(f"{file_name} found in env dir")
+                return path
+
+            # When the environment variable is set, don't look elsewhere
+            return None
+
+        # Then, look in the package's driver directory
+        if (path := pathlib.Path(__file__).parent / "rtk_fw" / file_name).is_file():
+            logger.debug(f"{file_name} found in package dir")
+            return path
+
+        # On Linux, check the system's FW directory
+        if (
+            platform.system() == "Linux"
+            and (path := pathlib.Path(RTK_LINUX_FIRMWARE_DIR) / file_name).is_file()
+        ):
+            logger.debug(f"{file_name} found in Linux system FW dir")
+            return path
+
+        # Finally look in the current directory
+        if (path := pathlib.Path.cwd() / file_name).is_file():
+            logger.debug(f"{file_name} found in CWD")
+            return path
+
+        return None
+
+    @staticmethod
+    def check(host):
+        if not host.hci_metadata:
+            logger.debug("USB metadata not found")
+            return False
+
+        vendor_id = host.hci_metadata.get("vendor_id", None)
+        product_id = host.hci_metadata.get("product_id", None)
+        if vendor_id is None or product_id is None:
+            logger.debug("USB metadata not sufficient")
+            return False
+
+        if (vendor_id, product_id) not in RTK_USB_PRODUCTS:
+            logger.debug(
+                f"USB device ({vendor_id:04X}, {product_id:04X}) " "not in known list"
+            )
+            return False
+
+        return True
+
+    @classmethod
+    async def driver_info_for_host(cls, host):
+        response = await host.send_command(
+            HCI_Read_Local_Version_Information_Command(), check_result=True
+        )
+        local_version = response.return_parameters
+
+        logger.debug(
+            f"looking for a driver: 0x{local_version.lmp_subversion:04X} "
+            f"(0x{local_version.hci_version:02X}, "
+            f"0x{local_version.hci_subversion:04X})"
+        )
+
+        driver_info = cls.find_driver_info(
+            local_version.hci_version,
+            local_version.hci_subversion,
+            local_version.lmp_subversion,
+        )
+        if driver_info is None:
+            # TODO: it seems that the Linux driver will send command (0x3f, 0x66)
+            # in this case and then re-read the local version, then re-match.
+            logger.debug("firmware already loaded or no known driver for this device")
+
+        return driver_info
+
+    @classmethod
+    async def for_host(cls, host, force=False):
+        # Check that a driver is needed for this host
+        if not force and not cls.check(host):
+            return None
+
+        # Get the driver info
+        driver_info = await cls.driver_info_for_host(host)
+        if driver_info is None:
+            return None
+
+        # Load the firmware
+        firmware_path = cls.find_binary_path(driver_info.fw_name)
+        if not firmware_path:
+            logger.warning(f"Firmware file {driver_info.fw_name} not found")
+            logger.warning("See https://google.github.io/bumble/drivers/realtek.html")
+            return None
+        with open(firmware_path, "rb") as firmware_file:
+            firmware = firmware_file.read()
+
+        # Load the config
+        config = None
+        if driver_info.config_name:
+            config_path = cls.find_binary_path(driver_info.config_name)
+            if config_path:
+                with open(config_path, "rb") as config_file:
+                    config = config_file.read()
+        if driver_info.config_needed and not config:
+            logger.warning("Config needed, but no config file available")
+            return None
+
+        return cls(host, driver_info, firmware, config)
+
+    def __init__(self, host, driver_info, firmware, config):
+        self.host = weakref.proxy(host)
+        self.driver_info = driver_info
+        self.firmware = firmware
+        self.config = config
+
+    @staticmethod
+    async def drop_firmware(host):
+        host.send_hci_packet(HCI_RTK_Drop_Firmware_Command())
+
+        # Wait for the command to be effective (no response is sent)
+        await asyncio.sleep(Driver.POST_DROP_DELAY)
+
+    async def download_for_rtl8723a(self):
+        # Check that the firmware image does not include an epatch signature.
+        if RTK_EPATCH_SIGNATURE in self.firmware:
+            logger.warning(
+                "epatch signature found in firmware, it is probably the wrong firmware"
+            )
+            return
+
+        # TODO: load the firmware
+
+    async def download_for_rtl8723b(self):
+        if self.driver_info.has_rom_version:
+            response = await self.host.send_command(
+                HCI_RTK_Read_ROM_Version_Command(), check_result=True
+            )
+            if response.return_parameters.status != HCI_SUCCESS:
+                logger.warning("can't get ROM version")
+                return
+            rom_version = response.return_parameters.version
+            logger.debug(f"ROM version before download: {rom_version:04X}")
+        else:
+            rom_version = 0
+
+        firmware = Firmware(self.firmware)
+        logger.debug(f"firmware: project_id=0x{firmware.project_id:04X}")
+        for patch in firmware.patches:
+            if patch[0] == rom_version + 1:
+                logger.debug(f"using patch {patch[0]}")
+                break
+        else:
+            logger.warning("no valid patch found for rom version {rom_version}")
+            return
+
+        # Append the config if there is one.
+        if self.config:
+            payload = patch[1] + self.config
+        else:
+            payload = patch[1]
+
+        # Download the payload, one fragment at a time.
+        fragment_count = math.ceil(len(payload) / RTK_FRAGMENT_LENGTH)
+        for fragment_index in range(fragment_count):
+            # NOTE: the Linux driver somehow adds 1 to the index after it wraps around.
+            # That's odd, but we"ll do the same here.
+            download_index = fragment_index & 0x7F
+            if download_index >= 0x80:
+                download_index += 1
+            if fragment_index == fragment_count - 1:
+                download_index |= 0x80  # End marker.
+            fragment_offset = fragment_index * RTK_FRAGMENT_LENGTH
+            fragment = payload[fragment_offset : fragment_offset + RTK_FRAGMENT_LENGTH]
+            logger.debug(f"downloading fragment {fragment_index}")
+            await self.host.send_command(
+                HCI_RTK_Download_Command(
+                    index=download_index, payload=fragment, check_result=True
+                )
+            )
+
+        logger.debug("download complete!")
+
+        # Read the version again
+        response = await self.host.send_command(
+            HCI_RTK_Read_ROM_Version_Command(), check_result=True
+        )
+        if response.return_parameters.status != HCI_SUCCESS:
+            logger.warning("can't get ROM version")
+        else:
+            rom_version = response.return_parameters.version
+            logger.debug(f"ROM version after download: {rom_version:04X}")
+
+    async def download_firmware(self):
+        if self.driver_info.rom == RTK_ROM_LMP_8723A:
+            return await self.download_for_rtl8723a()
+
+        if self.driver_info.rom in (
+            RTK_ROM_LMP_8723B,
+            RTK_ROM_LMP_8821A,
+            RTK_ROM_LMP_8761A,
+            RTK_ROM_LMP_8822B,
+            RTK_ROM_LMP_8852A,
+        ):
+            return await self.download_for_rtl8723b()
+
+        raise ValueError("ROM not supported")
+
+    async def init_controller(self):
+        await self.download_firmware()
+        await self.host.send_command(HCI_Reset_Command(), check_result=True)
+        logger.info(f"loaded FW image {self.driver_info.fw_name}")
diff --git a/bumble/gatt.py b/bumble/gatt.py
index ea2b690..067f31d 100644
--- a/bumble/gatt.py
+++ b/bumble/gatt.py
@@ -283,8 +283,7 @@
             f'IncludedServiceDefinition(handle=0x{self.handle:04X}, '
             f'group_starting_handle=0x{self.service.handle:04X}, '
             f'group_ending_handle=0x{self.service.end_group_handle:04X}, '
-            f'uuid={self.service.uuid}, '
-            f'{self.service.properties!s})'
+            f'uuid={self.service.uuid})'
         )
 
 
@@ -309,31 +308,33 @@
         AUTHENTICATED_SIGNED_WRITES = 0x40
         EXTENDED_PROPERTIES = 0x80
 
-        @staticmethod
-        def from_string(properties_str: str) -> Characteristic.Properties:
-            property_names: List[str] = []
-            for property in Characteristic.Properties:
-                if property.name is None:
-                    raise TypeError()
-                property_names.append(property.name)
-
-            def string_to_property(property_string) -> Characteristic.Properties:
-                for property in zip(Characteristic.Properties, property_names):
-                    if property_string == property[1]:
-                        return property[0]
-                raise TypeError(f"Unable to convert {property_string} to Property")
-
+        @classmethod
+        def from_string(cls, properties_str: str) -> Characteristic.Properties:
             try:
                 return functools.reduce(
-                    lambda x, y: x | string_to_property(y),
-                    properties_str.split(","),
+                    lambda x, y: x | cls[y],
+                    properties_str.replace("|", ",").split(","),
                     Characteristic.Properties(0),
                 )
-            except TypeError:
+            except (TypeError, KeyError):
+                # The check for `p.name is not None` here is needed because for InFlag
+                # enums, the .name property can be None, when the enum value is 0,
+                # so the type hint for .name is Optional[str].
+                enum_list: List[str] = [p.name for p in cls if p.name is not None]
+                enum_list_str = ",".join(enum_list)
                 raise TypeError(
-                    f"Characteristic.Properties::from_string() error:\nExpected a string containing any of the keys, separated by commas: {','.join(property_names)}\nGot: {properties_str}"
+                    f"Characteristic.Properties::from_string() error:\nExpected a string containing any of the keys, separated by , or |: {enum_list_str}\nGot: {properties_str}"
                 )
 
+        def __str__(self):
+            # NOTE: we override this method to offer a consistent result between python
+            # versions: the value returned by IntFlag.__str__() changed in version 11.
+            return '|'.join(
+                flag.name
+                for flag in Characteristic.Properties
+                if self.value & flag.value and flag.name is not None
+            )
+
     # For backwards compatibility these are defined here
     # For new code, please use Characteristic.Properties.X
     BROADCAST = Properties.BROADCAST
@@ -373,7 +374,7 @@
             f'Characteristic(handle=0x{self.handle:04X}, '
             f'end=0x{self.end_group_handle:04X}, '
             f'uuid={self.uuid}, '
-            f'{self.properties!s})'
+            f'{self.properties})'
         )
 
 
@@ -401,7 +402,7 @@
             f'CharacteristicDeclaration(handle=0x{self.handle:04X}, '
             f'value_handle=0x{self.value_handle:04X}, '
             f'uuid={self.characteristic.uuid}, '
-            f'{self.characteristic.properties!s})'
+            f'{self.characteristic.properties})'
         )
 
 
diff --git a/bumble/hci.py b/bumble/hci.py
index 9b5793d..0dbb127 100644
--- a/bumble/hci.py
+++ b/bumble/hci.py
@@ -62,7 +62,7 @@
     try:
         terminator = utf8_bytes.find(0)
         if terminator < 0:
-            return utf8_bytes
+            terminator = len(utf8_bytes)
         return utf8_bytes[0:terminator].decode('utf8')
     except UnicodeDecodeError:
         return utf8_bytes
@@ -185,7 +185,7 @@
 HCI_IO_CAPABILITY_RESPONSE_EVENT                                 = 0x32
 HCI_USER_CONFIRMATION_REQUEST_EVENT                              = 0x33
 HCI_USER_PASSKEY_REQUEST_EVENT                                   = 0x34
-HCI_REMOTE_OOB_DATA_REQUEST                                      = 0x35
+HCI_REMOTE_OOB_DATA_REQUEST_EVENT                                = 0x35
 HCI_SIMPLE_PAIRING_COMPLETE_EVENT                                = 0x36
 HCI_LINK_SUPERVISION_TIMEOUT_CHANGED_EVENT                       = 0x38
 HCI_ENHANCED_FLUSH_COMPLETE_EVENT                                = 0x39
@@ -1445,8 +1445,14 @@
     @staticmethod
     def init_from_fields(hci_object, fields, values):
         if isinstance(values, dict):
-            for field_name, _ in fields:
-                setattr(hci_object, field_name, values[field_name])
+            for field in fields:
+                if isinstance(field, list):
+                    # The field is an array, up-level the array field names
+                    for sub_field_name, _ in field:
+                        setattr(hci_object, sub_field_name, values[sub_field_name])
+                else:
+                    field_name = field[0]
+                    setattr(hci_object, field_name, values[field_name])
         else:
             for field_name, field_value in zip(fields, values):
                 setattr(hci_object, field_name, field_value)
@@ -1457,132 +1463,160 @@
         HCI_Object.init_from_fields(hci_object, parsed.keys(), parsed.values())
 
     @staticmethod
+    def parse_field(data, offset, field_type):
+        # The field_type may be a dictionary with a mapper, parser, and/or size
+        if isinstance(field_type, dict):
+            if 'size' in field_type:
+                field_type = field_type['size']
+            elif 'parser' in field_type:
+                field_type = field_type['parser']
+
+        # Parse the field
+        if field_type == '*':
+            # The rest of the bytes
+            field_value = data[offset:]
+            return (field_value, len(field_value))
+        if field_type == 1:
+            # 8-bit unsigned
+            return (data[offset], 1)
+        if field_type == -1:
+            # 8-bit signed
+            return (struct.unpack_from('b', data, offset)[0], 1)
+        if field_type == 2:
+            # 16-bit unsigned
+            return (struct.unpack_from('<H', data, offset)[0], 2)
+        if field_type == '>2':
+            # 16-bit unsigned big-endian
+            return (struct.unpack_from('>H', data, offset)[0], 2)
+        if field_type == -2:
+            # 16-bit signed
+            return (struct.unpack_from('<h', data, offset)[0], 2)
+        if field_type == 3:
+            # 24-bit unsigned
+            padded = data[offset : offset + 3] + bytes([0])
+            return (struct.unpack('<I', padded)[0], 3)
+        if field_type == 4:
+            # 32-bit unsigned
+            return (struct.unpack_from('<I', data, offset)[0], 4)
+        if field_type == '>4':
+            # 32-bit unsigned big-endian
+            return (struct.unpack_from('>I', data, offset)[0], 4)
+        if isinstance(field_type, int) and 4 < field_type <= 256:
+            # Byte array (from 5 up to 256 bytes)
+            return (data[offset : offset + field_type], field_type)
+        if callable(field_type):
+            new_offset, field_value = field_type(data, offset)
+            return (field_value, new_offset - offset)
+
+        raise ValueError(f'unknown field type {field_type}')
+
+    @staticmethod
     def dict_from_bytes(data, offset, fields):
         result = collections.OrderedDict()
-        for (field_name, field_type) in fields:
-            # The field_type may be a dictionary with a mapper, parser, and/or size
-            if isinstance(field_type, dict):
-                if 'size' in field_type:
-                    field_type = field_type['size']
-                elif 'parser' in field_type:
-                    field_type = field_type['parser']
-
-            # Parse the field
-            if field_type == '*':
-                # The rest of the bytes
-                field_value = data[offset:]
-                offset += len(field_value)
-            elif field_type == 1:
-                # 8-bit unsigned
-                field_value = data[offset]
+        for field in fields:
+            if isinstance(field, list):
+                # This is an array field, starting with a 1-byte item count.
+                item_count = data[offset]
                 offset += 1
-            elif field_type == -1:
-                # 8-bit signed
-                field_value = struct.unpack_from('b', data, offset)[0]
-                offset += 1
-            elif field_type == 2:
-                # 16-bit unsigned
-                field_value = struct.unpack_from('<H', data, offset)[0]
-                offset += 2
-            elif field_type == '>2':
-                # 16-bit unsigned big-endian
-                field_value = struct.unpack_from('>H', data, offset)[0]
-                offset += 2
-            elif field_type == -2:
-                # 16-bit signed
-                field_value = struct.unpack_from('<h', data, offset)[0]
-                offset += 2
-            elif field_type == 3:
-                # 24-bit unsigned
-                padded = data[offset : offset + 3] + bytes([0])
-                field_value = struct.unpack('<I', padded)[0]
-                offset += 3
-            elif field_type == 4:
-                # 32-bit unsigned
-                field_value = struct.unpack_from('<I', data, offset)[0]
-                offset += 4
-            elif field_type == '>4':
-                # 32-bit unsigned big-endian
-                field_value = struct.unpack_from('>I', data, offset)[0]
-                offset += 4
-            elif isinstance(field_type, int) and 4 < field_type <= 256:
-                # Byte array (from 5 up to 256 bytes)
-                field_value = data[offset : offset + field_type]
-                offset += field_type
-            elif callable(field_type):
-                offset, field_value = field_type(data, offset)
-            else:
-                raise ValueError(f'unknown field type {field_type}')
+                for _ in range(item_count):
+                    for sub_field_name, sub_field_type in field:
+                        value, size = HCI_Object.parse_field(
+                            data, offset, sub_field_type
+                        )
+                        result.setdefault(sub_field_name, []).append(value)
+                        offset += size
+                continue
 
+            field_name, field_type = field
+            field_value, field_size = HCI_Object.parse_field(data, offset, field_type)
             result[field_name] = field_value
+            offset += field_size
 
         return result
 
     @staticmethod
+    def serialize_field(field_value, field_type):
+        # The field_type may be a dictionary with a mapper, parser, serializer,
+        # and/or size
+        serializer = None
+        if isinstance(field_type, dict):
+            if 'serializer' in field_type:
+                serializer = field_type['serializer']
+            if 'size' in field_type:
+                field_type = field_type['size']
+
+        # Serialize the field
+        if serializer:
+            field_bytes = serializer(field_value)
+        elif field_type == 1:
+            # 8-bit unsigned
+            field_bytes = bytes([field_value])
+        elif field_type == -1:
+            # 8-bit signed
+            field_bytes = struct.pack('b', field_value)
+        elif field_type == 2:
+            # 16-bit unsigned
+            field_bytes = struct.pack('<H', field_value)
+        elif field_type == '>2':
+            # 16-bit unsigned big-endian
+            field_bytes = struct.pack('>H', field_value)
+        elif field_type == -2:
+            # 16-bit signed
+            field_bytes = struct.pack('<h', field_value)
+        elif field_type == 3:
+            # 24-bit unsigned
+            field_bytes = struct.pack('<I', field_value)[0:3]
+        elif field_type == 4:
+            # 32-bit unsigned
+            field_bytes = struct.pack('<I', field_value)
+        elif field_type == '>4':
+            # 32-bit unsigned big-endian
+            field_bytes = struct.pack('>I', field_value)
+        elif field_type == '*':
+            if isinstance(field_value, int):
+                if 0 <= field_value <= 255:
+                    field_bytes = bytes([field_value])
+                else:
+                    raise ValueError('value too large for *-typed field')
+            else:
+                field_bytes = bytes(field_value)
+        elif isinstance(field_value, (bytes, bytearray)) or hasattr(
+            field_value, 'to_bytes'
+        ):
+            field_bytes = bytes(field_value)
+            if isinstance(field_type, int) and 4 < field_type <= 256:
+                # Truncate or pad with zeros if the field is too long or too short
+                if len(field_bytes) < field_type:
+                    field_bytes += bytes(field_type - len(field_bytes))
+                elif len(field_bytes) > field_type:
+                    field_bytes = field_bytes[:field_type]
+        else:
+            raise ValueError(f"don't know how to serialize type {type(field_value)}")
+
+        return field_bytes
+
+    @staticmethod
     def dict_to_bytes(hci_object, fields):
         result = bytearray()
-        for (field_name, field_type) in fields:
-            # The field_type may be a dictionary with a mapper, parser, serializer,
-            # and/or size
-            serializer = None
-            if isinstance(field_type, dict):
-                if 'serializer' in field_type:
-                    serializer = field_type['serializer']
-                if 'size' in field_type:
-                    field_type = field_type['size']
-
-            # Serialize the field
-            field_value = hci_object[field_name]
-            if serializer:
-                field_bytes = serializer(field_value)
-            elif field_type == 1:
-                # 8-bit unsigned
-                field_bytes = bytes([field_value])
-            elif field_type == -1:
-                # 8-bit signed
-                field_bytes = struct.pack('b', field_value)
-            elif field_type == 2:
-                # 16-bit unsigned
-                field_bytes = struct.pack('<H', field_value)
-            elif field_type == '>2':
-                # 16-bit unsigned big-endian
-                field_bytes = struct.pack('>H', field_value)
-            elif field_type == -2:
-                # 16-bit signed
-                field_bytes = struct.pack('<h', field_value)
-            elif field_type == 3:
-                # 24-bit unsigned
-                field_bytes = struct.pack('<I', field_value)[0:3]
-            elif field_type == 4:
-                # 32-bit unsigned
-                field_bytes = struct.pack('<I', field_value)
-            elif field_type == '>4':
-                # 32-bit unsigned big-endian
-                field_bytes = struct.pack('>I', field_value)
-            elif field_type == '*':
-                if isinstance(field_value, int):
-                    if 0 <= field_value <= 255:
-                        field_bytes = bytes([field_value])
-                    else:
-                        raise ValueError('value too large for *-typed field')
-                else:
-                    field_bytes = bytes(field_value)
-            elif isinstance(field_value, (bytes, bytearray)) or hasattr(
-                field_value, 'to_bytes'
-            ):
-                field_bytes = bytes(field_value)
-                if isinstance(field_type, int) and 4 < field_type <= 256:
-                    # Truncate or Pad with zeros if the field is too long or too short
-                    if len(field_bytes) < field_type:
-                        field_bytes += bytes(field_type - len(field_bytes))
-                    elif len(field_bytes) > field_type:
-                        field_bytes = field_bytes[:field_type]
-            else:
-                raise ValueError(
-                    f"don't know how to serialize type {type(field_value)}"
+        for field in fields:
+            if isinstance(field, list):
+                # The field is an array. The serialized form starts with a 1-byte
+                # item count. We use the length of the first array field as the
+                # array count, since all array fields have the same number of items.
+                item_count = len(hci_object[field[0][0]])
+                result += bytes([item_count]) + b''.join(
+                    b''.join(
+                        HCI_Object.serialize_field(
+                            hci_object[sub_field_name][i], sub_field_type
+                        )
+                        for sub_field_name, sub_field_type in field
+                    )
+                    for i in range(item_count)
                 )
+                continue
 
-            result += field_bytes
+            (field_name, field_type) = field
+            result += HCI_Object.serialize_field(hci_object[field_name], field_type)
 
         return bytes(result)
 
@@ -1617,46 +1651,73 @@
         return str(value)
 
     @staticmethod
-    def format_fields(hci_object, keys, indentation='', value_mappers=None):
-        if not keys:
-            return ''
+    def stringify_field(
+        field_name, field_type, field_value, indentation, value_mappers
+    ):
+        value_mapper = None
+        if isinstance(field_type, dict):
+            # Get the value mapper from the specifier
+            value_mapper = field_type.get('mapper')
 
-        # Measure the widest field name
-        max_field_name_length = max(
-            (len(key[0] if isinstance(key, tuple) else key) for key in keys)
+        # Check if there's a matching mapper passed
+        if value_mappers:
+            value_mapper = value_mappers.get(field_name, value_mapper)
+
+        # Map the value if we have a mapper
+        if value_mapper is not None:
+            field_value = value_mapper(field_value)
+
+        # Get the string representation of the value
+        return HCI_Object.format_field_value(
+            field_value, indentation=indentation + '  '
         )
 
+    @staticmethod
+    def format_fields(hci_object, fields, indentation='', value_mappers=None):
+        if not fields:
+            return ''
+
         # Build array of formatted key:value pairs
-        fields = []
-        for key in keys:
-            value_mapper = None
-            if isinstance(key, tuple):
-                # The key has an associated specifier
-                key, specifier = key
+        field_strings = []
+        for field in fields:
+            if isinstance(field, list):
+                for sub_field in field:
+                    sub_field_name, sub_field_type = sub_field
+                    item_count = len(hci_object[sub_field_name])
+                    for i in range(item_count):
+                        field_strings.append(
+                            (
+                                f'{sub_field_name}[{i}]',
+                                HCI_Object.stringify_field(
+                                    sub_field_name,
+                                    sub_field_type,
+                                    hci_object[sub_field_name][i],
+                                    indentation,
+                                    value_mappers,
+                                ),
+                            ),
+                        )
+                continue
 
-                # Get the value mapper from the specifier
-                if isinstance(specifier, dict):
-                    value_mapper = specifier.get('mapper')
-
-            # Get the value for the field
-            value = hci_object[key]
-
-            # Map the value if needed
-            if value_mappers:
-                value_mapper = value_mappers.get(key, value_mapper)
-            if value_mapper is not None:
-                value = value_mapper(value)
-
-            # Get the string representation of the value
-            value_str = HCI_Object.format_field_value(
-                value, indentation=indentation + '  '
+            field_name, field_type = field
+            field_value = hci_object[field_name]
+            field_strings.append(
+                (
+                    field_name,
+                    HCI_Object.stringify_field(
+                        field_name, field_type, field_value, indentation, value_mappers
+                    ),
+                ),
             )
 
-            # Add the field to the formatted result
-            key_str = color(f'{key + ":":{1 + max_field_name_length}}', 'cyan')
-            fields.append(f'{indentation}{key_str} {value_str}')
-
-        return '\n'.join(fields)
+        # Measure the widest field name
+        max_field_name_length = max(len(s[0]) for s in field_strings)
+        sep = ':'
+        return '\n'.join(
+            f'{indentation}'
+            f'{color(f"{field_name + sep:{1 + max_field_name_length}}", "cyan")} {field_value}'
+            for field_name, field_value in field_strings
+        )
 
     def __bytes__(self):
         return self.to_bytes()
@@ -1795,6 +1856,16 @@
     def to_bytes(self):
         return self.address_bytes
 
+    def to_string(self, with_type_qualifier=True):
+        '''
+        String representation of the address, MSB first, with an optional type
+        qualifier.
+        '''
+        result = ':'.join([f'{x:02X}' for x in reversed(self.address_bytes)])
+        if not with_type_qualifier or not self.is_public:
+            return result
+        return result + '/P'
+
     def __bytes__(self):
         return self.to_bytes()
 
@@ -1808,13 +1879,7 @@
         )
 
     def __str__(self):
-        '''
-        String representation of the address, MSB first
-        '''
-        result = ':'.join([f'{x:02X}' for x in reversed(self.address_bytes)])
-        if not self.is_public:
-            return result
-        return result + '/P'
+        return self.to_string()
 
 
 # Predefined address values
@@ -2284,6 +2349,55 @@
 
 # -----------------------------------------------------------------------------
 @HCI_Command.command(
+    fields=[
+        ('bd_addr', Address.parse_address),
+        ('c', 16),
+        ('r', 16),
+    ],
+    return_parameters_fields=[
+        ('status', STATUS_SPEC),
+        ('bd_addr', Address.parse_address),
+    ],
+)
+class HCI_Remote_OOB_Data_Request_Reply_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.34 Remote OOB Data Request Reply Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    fields=[('bd_addr', Address.parse_address)],
+    return_parameters_fields=[
+        ('status', STATUS_SPEC),
+        ('bd_addr', Address.parse_address),
+    ],
+)
+class HCI_Remote_OOB_Data_Request_Negative_Reply_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.35 Remote OOB Data Request Negative Reply Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    fields=[
+        ('bd_addr', Address.parse_address),
+        ('reason', 1),
+    ],
+    return_parameters_fields=[
+        ('status', STATUS_SPEC),
+        ('bd_addr', Address.parse_address),
+    ],
+)
+class HCI_IO_Capability_Request_Negative_Reply_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.36 IO Capability Request Negative Reply Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
     [
         ('connection_handle', 2),
         ('transmit_bandwidth', 4),
@@ -2320,6 +2434,161 @@
 # -----------------------------------------------------------------------------
 @HCI_Command.command(
     [
+        ('bd_addr', Address.parse_address),
+        ('transmit_bandwidth', 4),
+        ('receive_bandwidth', 4),
+        ('transmit_coding_format', 5),
+        ('receive_coding_format', 5),
+        ('transmit_codec_frame_size', 2),
+        ('receive_codec_frame_size', 2),
+        ('input_bandwidth', 4),
+        ('output_bandwidth', 4),
+        ('input_coding_format', 5),
+        ('output_coding_format', 5),
+        ('input_coded_data_size', 2),
+        ('output_coded_data_size', 2),
+        ('input_pcm_data_format', 1),
+        ('output_pcm_data_format', 1),
+        ('input_pcm_sample_payload_msb_position', 1),
+        ('output_pcm_sample_payload_msb_position', 1),
+        ('input_data_path', 1),
+        ('output_data_path', 1),
+        ('input_transport_unit_size', 1),
+        ('output_transport_unit_size', 1),
+        ('max_latency', 2),
+        ('packet_type', 2),
+        ('retransmission_effort', 1),
+    ]
+)
+class HCI_Enhanced_Accept_Synchronous_Connection_Request_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.46 Enhanced Accept Synchronous Connection Request Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    fields=[
+        ('bd_addr', Address.parse_address),
+        ('page_scan_repetition_mode', 1),
+        ('clock_offset', 2),
+    ]
+)
+class HCI_Truncated_Page_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.47 Truncated Page Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    fields=[('bd_addr', Address.parse_address)],
+    return_parameters_fields=[
+        ('status', STATUS_SPEC),
+        ('bd_addr', Address.parse_address),
+    ],
+)
+class HCI_Truncated_Page_Cancel_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.48 Truncated Page Cancel Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    fields=[
+        ('enable', 1),
+        ('lt_addr', 1),
+        ('lpo_allowed', 1),
+        ('packet_type', 2),
+        ('interval_min', 2),
+        ('interval_max', 2),
+        ('supervision_timeout', 2),
+    ],
+    return_parameters_fields=[
+        ('status', STATUS_SPEC),
+        ('lt_addr', 1),
+        ('interval', 2),
+    ],
+)
+class HCI_Set_Connectionless_Peripheral_Broadcast_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.49 Set Connectionless Peripheral Broadcast Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    fields=[
+        ('enable', 1),
+        ('bd_addr', Address.parse_address),
+        ('lt_addr', 1),
+        ('interval', 2),
+        ('clock_offset', 4),
+        ('next_connectionless_peripheral_broadcast_clock', 4),
+        ('supervision_timeout', 2),
+        ('remote_timing_accuracy', 1),
+        ('skip', 1),
+        ('packet_type', 2),
+        ('afh_channel_map', 10),
+    ],
+    return_parameters_fields=[
+        ('status', STATUS_SPEC),
+        ('bd_addr', Address.parse_address),
+        ('lt_addr', 1),
+    ],
+)
+class HCI_Set_Connectionless_Peripheral_Broadcast_Receive_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.50 Set Connectionless Peripheral Broadcast Receive Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+class HCI_Start_Synchronization_Train_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.51 Start Synchronization Train Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    fields=[
+        ('bd_addr', Address.parse_address),
+        ('sync_scan_timeout', 2),
+        ('sync_scan_window', 2),
+        ('sync_scan_interval', 2),
+    ],
+)
+class HCI_Receive_Synchronization_Train_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.52 Receive Synchronization Train Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    fields=[
+        ('bd_addr', Address.parse_address),
+        ('c_192', 16),
+        ('r_192', 16),
+        ('c_256', 16),
+        ('r_256', 16),
+    ],
+    return_parameters_fields=[
+        ('status', STATUS_SPEC),
+        ('bd_addr', Address.parse_address),
+    ],
+)
+class HCI_Remote_OOB_Extended_Data_Request_Reply_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.1.53 Remote OOB Extended Data Request Reply Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    [
         ('connection_handle', 2),
         ('sniff_max_interval', 2),
         ('sniff_min_interval', 2),
@@ -2685,6 +2954,20 @@
 
 # -----------------------------------------------------------------------------
 @HCI_Command.command(
+    return_parameters_fields=[
+        ('status', STATUS_SPEC),
+        ('c', 16),
+        ('r', 16),
+    ]
+)
+class HCI_Read_Local_OOB_Data_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.3.60 Read Local OOB Data Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
     return_parameters_fields=[('status', STATUS_SPEC), ('tx_power', -1)]
 )
 class HCI_Read_Inquiry_Response_Transmit_Power_Level_Command(HCI_Command):
@@ -2747,6 +3030,22 @@
 @HCI_Command.command(
     return_parameters_fields=[
         ('status', STATUS_SPEC),
+        ('c_192', 16),
+        ('r_192', 16),
+        ('c_256', 16),
+        ('r_256', 16),
+    ]
+)
+class HCI_Read_Local_OOB_Extended_Data_Command(HCI_Command):
+    '''
+    See Bluetooth spec @ 7.3.95 Read Local OOB Extended Data Command
+    '''
+
+
+# -----------------------------------------------------------------------------
+@HCI_Command.command(
+    return_parameters_fields=[
+        ('status', STATUS_SPEC),
         ('hci_version', 1),
         ('hci_subversion', 2),
         ('lmp_version', 1),
@@ -3529,9 +3828,7 @@
             'advertising_data',
             {
                 'parser': HCI_Object.parse_length_prefixed_bytes,
-                'serializer': functools.partial(
-                    HCI_Object.serialize_length_prefixed_bytes
-                ),
+                'serializer': HCI_Object.serialize_length_prefixed_bytes,
             },
         ),
     ]
@@ -3579,9 +3876,7 @@
             'scan_response_data',
             {
                 'parser': HCI_Object.parse_length_prefixed_bytes,
-                'serializer': functools.partial(
-                    HCI_Object.serialize_length_prefixed_bytes
-                ),
+                'serializer': HCI_Object.serialize_length_prefixed_bytes,
             },
         ),
     ]
@@ -3609,73 +3904,21 @@
 
 
 # -----------------------------------------------------------------------------
-@HCI_Command.command(fields=None)
+@HCI_Command.command(
+    [
+        ('enable', 1),
+        [
+            ('advertising_handles', 1),
+            ('durations', 2),
+            ('max_extended_advertising_events', 1),
+        ],
+    ]
+)
 class HCI_LE_Set_Extended_Advertising_Enable_Command(HCI_Command):
     '''
     See Bluetooth spec @ 7.8.56 LE Set Extended Advertising Enable Command
     '''
 
-    @classmethod
-    def from_parameters(cls, parameters):
-        enable = parameters[0]
-        num_sets = parameters[1]
-        advertising_handles = []
-        durations = []
-        max_extended_advertising_events = []
-        offset = 2
-        for _ in range(num_sets):
-            advertising_handles.append(parameters[offset])
-            durations.append(struct.unpack_from('<H', parameters, offset + 1)[0])
-            max_extended_advertising_events.append(parameters[offset + 3])
-            offset += 4
-
-        return cls(
-            enable, advertising_handles, durations, max_extended_advertising_events
-        )
-
-    def __init__(
-        self, enable, advertising_handles, durations, max_extended_advertising_events
-    ):
-        super().__init__(HCI_LE_SET_EXTENDED_ADVERTISING_ENABLE_COMMAND)
-        self.enable = enable
-        self.advertising_handles = advertising_handles
-        self.durations = durations
-        self.max_extended_advertising_events = max_extended_advertising_events
-
-        self.parameters = bytes([enable, len(advertising_handles)]) + b''.join(
-            [
-                struct.pack(
-                    '<BHB',
-                    advertising_handles[i],
-                    durations[i],
-                    max_extended_advertising_events[i],
-                )
-                for i in range(len(advertising_handles))
-            ]
-        )
-
-    def __str__(self):
-        fields = [('enable:', self.enable)]
-        for i, advertising_handle in enumerate(self.advertising_handles):
-            fields.append(
-                (f'advertising_handle[{i}]:             ', advertising_handle)
-            )
-            fields.append((f'duration[{i}]:                       ', self.durations[i]))
-            fields.append(
-                (
-                    f'max_extended_advertising_events[{i}]:',
-                    self.max_extended_advertising_events[i],
-                )
-            )
-
-        return (
-            color(self.name, 'green')
-            + ':\n'
-            + '\n'.join(
-                [color(field[0], 'cyan') + ' ' + str(field[1]) for field in fields]
-            )
-        )
-
 
 # -----------------------------------------------------------------------------
 @HCI_Command.command(
@@ -3826,7 +4069,10 @@
             color(self.name, 'green')
             + ':\n'
             + '\n'.join(
-                [color(field[0], 'cyan') + ' ' + str(field[1]) for field in fields]
+                [
+                    color('  ' + field[0], 'cyan') + ' ' + str(field[1])
+                    for field in fields
+                ]
             )
         )
 
@@ -4002,7 +4248,10 @@
             color(self.name, 'green')
             + ':\n'
             + '\n'.join(
-                [color(field[0], 'cyan') + ' ' + str(field[1]) for field in fields]
+                [
+                    color('  ' + field[0], 'cyan') + ' ' + str(field[1])
+                    for field in fields
+                ]
             )
         )
 
@@ -4965,7 +5214,7 @@
     def __str__(self):
         lines = [
             color(self.name, 'magenta') + ':',
-            color('  number_of_handles:         ', 'cyan')
+            color('  number_of_handles:        ', 'cyan')
             + f'{len(self.connection_handles)}',
         ]
         for i, connection_handle in enumerate(self.connection_handles):
@@ -5300,6 +5549,14 @@
 
 
 # -----------------------------------------------------------------------------
+@HCI_Event.event([('bd_addr', Address.parse_address)])
+class HCI_Remote_OOB_Data_Request_Event(HCI_Event):
+    '''
+    See Bluetooth spec @ 7.7.44 Remote OOB Data Request Event
+    '''
+
+
+# -----------------------------------------------------------------------------
 @HCI_Event.event([('status', STATUS_SPEC), ('bd_addr', Address.parse_address)])
 class HCI_Simple_Pairing_Complete_Event(HCI_Event):
     '''
@@ -5316,6 +5573,14 @@
 
 
 # -----------------------------------------------------------------------------
+@HCI_Event.event([('handle', 2)])
+class HCI_Enhanced_Flush_Complete_Event(HCI_Event):
+    '''
+    See Bluetooth spec @ 7.7.47 Enhanced Flush Complete Event
+    '''
+
+
+# -----------------------------------------------------------------------------
 @HCI_Event.event([('bd_addr', Address.parse_address), ('passkey', 4)])
 class HCI_User_Passkey_Notification_Event(HCI_Event):
     '''
@@ -5324,6 +5589,14 @@
 
 
 # -----------------------------------------------------------------------------
+@HCI_Event.event([('bd_addr', Address.parse_address), ('notification_type', 1)])
+class HCI_Keypress_Notification_Event(HCI_Event):
+    '''
+    See Bluetooth spec @ 7.7.49 Keypress Notification Event
+    '''
+
+
+# -----------------------------------------------------------------------------
 @HCI_Event.event([('bd_addr', Address.parse_address), ('host_supported_features', 8)])
 class HCI_Remote_Host_Supported_Features_Notification_Event(HCI_Event):
     '''
@@ -5373,7 +5646,7 @@
     def __str__(self):
         return (
             f'{color("ACL", "blue")}: '
-            f'handle=0x{self.connection_handle:04x}'
+            f'handle=0x{self.connection_handle:04x}, '
             f'pb={self.pb_flag}, bc={self.bc_flag}, '
             f'data_total_length={self.data_total_length}, '
             f'data={self.data.hex()}'
diff --git a/bumble/hfp.py b/bumble/hfp.py
index 7bb9f08..9080a55 100644
--- a/bumble/hfp.py
+++ b/bumble/hfp.py
@@ -18,10 +18,11 @@
 import logging
 import asyncio
 import collections
+from typing import Union
 
+from . import rfcomm
 from .colors import color
 
-
 # -----------------------------------------------------------------------------
 # Logging
 # -----------------------------------------------------------------------------
@@ -34,7 +35,12 @@
 
 # -----------------------------------------------------------------------------
 class HfpProtocol:
-    def __init__(self, dlc):
+    dlc: rfcomm.DLC
+    buffer: str
+    lines: collections.deque
+    lines_available: asyncio.Event
+
+    def __init__(self, dlc: rfcomm.DLC) -> None:
         self.dlc = dlc
         self.buffer = ''
         self.lines = collections.deque()
@@ -42,7 +48,7 @@
 
         dlc.sink = self.feed
 
-    def feed(self, data):
+    def feed(self, data: Union[bytes, str]) -> None:
         # Convert the data to a string if needed
         if isinstance(data, bytes):
             data = data.decode('utf-8')
@@ -57,19 +63,19 @@
             if len(line) > 0:
                 self.on_line(line)
 
-    def on_line(self, line):
+    def on_line(self, line: str) -> None:
         self.lines.append(line)
         self.lines_available.set()
 
-    def send_command_line(self, line):
+    def send_command_line(self, line: str) -> None:
         logger.debug(color(f'>>> {line}', 'yellow'))
         self.dlc.write(line + '\r')
 
-    def send_response_line(self, line):
+    def send_response_line(self, line: str) -> None:
         logger.debug(color(f'>>> {line}', 'yellow'))
         self.dlc.write('\r\n' + line + '\r\n')
 
-    async def next_line(self):
+    async def next_line(self) -> str:
         await self.lines_available.wait()
         line = self.lines.popleft()
         if not self.lines:
@@ -77,7 +83,7 @@
         logger.debug(color(f'<<< {line}', 'green'))
         return line
 
-    async def initialize_service(self):
+    async def initialize_service(self) -> None:
         # Perform Service Level Connection Initialization
         self.send_command_line('AT+BRSF=2072')  # Retrieve Supported Features
         await (self.next_line())
diff --git a/bumble/host.py b/bumble/host.py
index afde2ee..e41fd02 100644
--- a/bumble/host.py
+++ b/bumble/host.py
@@ -23,6 +23,7 @@
 from bumble.colors import color
 from bumble.l2cap import L2CAP_PDU
 from bumble.snoop import Snooper
+from bumble import drivers
 
 from typing import Optional
 
@@ -62,6 +63,7 @@
     HCI_Read_Local_Version_Information_Command,
     HCI_Reset_Command,
     HCI_Set_Event_Mask_Command,
+    map_null_terminated_utf8_string,
 )
 from .core import (
     BT_BR_EDR_TRANSPORT,
@@ -115,6 +117,7 @@
         super().__init__()
 
         self.hci_sink = None
+        self.hci_metadata = None
         self.ready = False  # True when we can accept incoming packets
         self.reset_done = False
         self.connections = {}  # Connections, by connection handle
@@ -140,6 +143,9 @@
         # Connect to the source and sink if specified
         if controller_source:
             controller_source.set_packet_sink(self)
+            self.hci_metadata = getattr(
+                controller_source, 'metadata', self.hci_metadata
+            )
         if controller_sink:
             self.set_packet_sink(controller_sink)
 
@@ -169,7 +175,7 @@
         self.emit('flush')
         self.command_semaphore.release()
 
-    async def reset(self):
+    async def reset(self, driver_factory=drivers.get_driver_for_host):
         if self.ready:
             self.ready = False
             await self.flush()
@@ -177,6 +183,15 @@
         await self.send_command(HCI_Reset_Command(), check_result=True)
         self.ready = True
 
+        # Instantiate and init a driver for the host if needed.
+        # NOTE: we don't keep a reference to the driver here, because we don't
+        # currently have a need for the driver later on. But if the driver interface
+        # evolves, it may be required, then, to store a reference to the driver in
+        # an object property.
+        if driver_factory is not None:
+            if driver := await driver_factory(self):
+                await driver.init_controller()
+
         response = await self.send_command(
             HCI_Read_Local_Supported_Commands_Command(), check_result=True
         )
@@ -297,7 +312,7 @@
         if self.snooper:
             self.snooper.snoop(bytes(packet), Snooper.Direction.HOST_TO_CONTROLLER)
 
-        self.hci_sink.on_packet(packet.to_bytes())
+        self.hci_sink.on_packet(bytes(packet))
 
     async def send_command(self, command, check_result=False):
         logger.debug(f'{color("### HOST -> CONTROLLER", "blue")}: {command}')
@@ -349,7 +364,7 @@
         asyncio.create_task(send_command(command))
 
     def send_l2cap_pdu(self, connection_handle, cid, pdu):
-        l2cap_pdu = L2CAP_PDU(cid, pdu).to_bytes()
+        l2cap_pdu = bytes(L2CAP_PDU(cid, pdu))
 
         # Send the data to the controller via ACL packets
         bytes_remaining = len(l2cap_pdu)
@@ -887,7 +902,12 @@
         if event.status != HCI_SUCCESS:
             self.emit('remote_name_failure', event.bd_addr, event.status)
         else:
-            self.emit('remote_name', event.bd_addr, event.remote_name)
+            utf8_name = event.remote_name
+            terminator = utf8_name.find(0)
+            if terminator >= 0:
+                utf8_name = utf8_name[0:terminator]
+
+            self.emit('remote_name', event.bd_addr, utf8_name)
 
     def on_hci_remote_host_supported_features_notification_event(self, event):
         self.emit(
diff --git a/bumble/keys.py b/bumble/keys.py
index a30e753..198d5c4 100644
--- a/bumble/keys.py
+++ b/bumble/keys.py
@@ -190,10 +190,44 @@
 
 # -----------------------------------------------------------------------------
 class JsonKeyStore(KeyStore):
+    """
+    KeyStore implementation that is backed by a JSON file.
+
+    This implementation supports storing a hierarchy of key sets in a single file.
+    A key set is a representation of a PairingKeys object. Each key set is stored
+    in a map, with the address of paired peer as the key. Maps are themselves grouped
+    into namespaces, grouping pairing keys by controller addresses.
+    The JSON object model looks like:
+    {
+        "<namespace>": {
+            "peer-address": {
+                "address_type": <n>,
+                "irk" : {
+                    "authenticated": <true/false>,
+                    "value": "hex-encoded-key"
+                },
+                ... other keys ...
+            },
+            ... other peers ...
+        }
+        ... other namespaces ...
+    }
+
+    A namespace is typically the BD_ADDR of a controller, since that is a convenient
+    unique identifier, but it may be something else.
+    A special namespace, called the "default" namespace, is used when instantiating this
+    class without a namespace. With the default namespace, reading from a file will
+    load an existing namespace if there is only one, which may be convenient for reading
+    from a file with a single key set and for which the namespace isn't known. If the
+    file does not include any existing key set, or if there are more than one and none
+    has the default name, a new one will be created with the name "__DEFAULT__".
+    """
+
     APP_NAME = 'Bumble'
     APP_AUTHOR = 'Google'
     KEYS_DIR = 'Pairing'
     DEFAULT_NAMESPACE = '__DEFAULT__'
+    DEFAULT_BASE_NAME = "keys"
 
     def __init__(self, namespace, filename=None):
         self.namespace = namespace if namespace is not None else self.DEFAULT_NAMESPACE
@@ -208,8 +242,9 @@
             self.directory_name = os.path.join(
                 appdirs.user_data_dir(self.APP_NAME, self.APP_AUTHOR), self.KEYS_DIR
             )
+            base_name = self.DEFAULT_BASE_NAME if namespace is None else self.namespace
             json_filename = (
-                f'{self.namespace}.json'.lower().replace(':', '-').replace('/p', '-p')
+                f'{base_name}.json'.lower().replace(':', '-').replace('/p', '-p')
             )
             self.filename = os.path.join(self.directory_name, json_filename)
         else:
@@ -219,11 +254,13 @@
         logger.debug(f'JSON keystore: {self.filename}')
 
     @staticmethod
-    def from_device(device: Device) -> Optional[JsonKeyStore]:
-        if not device.config.keystore:
-            return None
-
-        params = device.config.keystore.split(':', 1)[1:]
+    def from_device(device: Device, filename=None) -> Optional[JsonKeyStore]:
+        if not filename:
+            # Extract the filename from the config if there is one
+            if device.config.keystore is not None:
+                params = device.config.keystore.split(':', 1)[1:]
+                if params:
+                    filename = params[0]
 
         # Use a namespace based on the device address
         if device.public_address not in (Address.ANY, Address.ANY_RANDOM):
@@ -232,19 +269,31 @@
             namespace = str(device.random_address)
         else:
             namespace = JsonKeyStore.DEFAULT_NAMESPACE
-        if params:
-            filename = params[0]
-        else:
-            filename = None
 
         return JsonKeyStore(namespace, filename)
 
     async def load(self):
+        # Try to open the file, without failing. If the file does not exist, it
+        # will be created upon saving.
         try:
             with open(self.filename, 'r', encoding='utf-8') as json_file:
-                return json.load(json_file)
+                db = json.load(json_file)
         except FileNotFoundError:
-            return {}
+            db = {}
+
+        # First, look for a namespace match
+        if self.namespace in db:
+            return (db, db[self.namespace])
+
+        # Then, if the namespace is the default namespace, and there's
+        # only one entry in the db, use that
+        if self.namespace == self.DEFAULT_NAMESPACE and len(db) == 1:
+            return next(iter(db.items()))
+
+        # Finally, just create an empty key map for the namespace
+        key_map = {}
+        db[self.namespace] = key_map
+        return (db, key_map)
 
     async def save(self, db):
         # Create the directory if it doesn't exist
@@ -260,53 +309,30 @@
         os.replace(temp_filename, self.filename)
 
     async def delete(self, name: str) -> None:
-        db = await self.load()
-
-        namespace = db.get(self.namespace)
-        if namespace is None:
-            raise KeyError(name)
-
-        del namespace[name]
+        db, key_map = await self.load()
+        del key_map[name]
         await self.save(db)
 
     async def update(self, name, keys):
-        db = await self.load()
-
-        namespace = db.setdefault(self.namespace, {})
-        namespace.setdefault(name, {}).update(keys.to_dict())
-
+        db, key_map = await self.load()
+        key_map.setdefault(name, {}).update(keys.to_dict())
         await self.save(db)
 
     async def get_all(self):
-        db = await self.load()
-
-        namespace = db.get(self.namespace)
-        if namespace is None:
-            return []
-
-        return [
-            (name, PairingKeys.from_dict(keys)) for (name, keys) in namespace.items()
-        ]
+        _, key_map = await self.load()
+        return [(name, PairingKeys.from_dict(keys)) for (name, keys) in key_map.items()]
 
     async def delete_all(self):
-        db = await self.load()
-
-        db.pop(self.namespace, None)
-
+        db, key_map = await self.load()
+        key_map.clear()
         await self.save(db)
 
     async def get(self, name: str) -> Optional[PairingKeys]:
-        db = await self.load()
-
-        namespace = db.get(self.namespace)
-        if namespace is None:
+        _, key_map = await self.load()
+        if name not in key_map:
             return None
 
-        keys = namespace.get(name)
-        if keys is None:
-            return None
-
-        return PairingKeys.from_dict(keys)
+        return PairingKeys.from_dict(key_map[name])
 
 
 # -----------------------------------------------------------------------------
diff --git a/bumble/l2cap.py b/bumble/l2cap.py
index ef7fdab..4464afc 100644
--- a/bumble/l2cap.py
+++ b/bumble/l2cap.py
@@ -22,7 +22,19 @@
 
 from collections import deque
 from pyee import EventEmitter
-from typing import Dict, Type
+from typing import (
+    Dict,
+    Type,
+    List,
+    Optional,
+    Tuple,
+    Callable,
+    Any,
+    Union,
+    Deque,
+    Iterable,
+    TYPE_CHECKING,
+)
 
 from .colors import color
 from .core import BT_CENTRAL_ROLE, InvalidStateError, ProtocolError
@@ -33,6 +45,9 @@
     name_or_number,
 )
 
+if TYPE_CHECKING:
+    from bumble.device import Connection
+
 # -----------------------------------------------------------------------------
 # Logging
 # -----------------------------------------------------------------------------
@@ -155,7 +170,7 @@
     '''
 
     @staticmethod
-    def from_bytes(data):
+    def from_bytes(data: bytes) -> L2CAP_PDU:
         # Sanity check
         if len(data) < 4:
             raise ValueError('not enough data for L2CAP header')
@@ -165,18 +180,18 @@
 
         return L2CAP_PDU(l2cap_pdu_cid, l2cap_pdu_payload)
 
-    def to_bytes(self):
+    def to_bytes(self) -> bytes:
         header = struct.pack('<HH', len(self.payload), self.cid)
         return header + self.payload
 
-    def __init__(self, cid, payload):
+    def __init__(self, cid: int, payload: bytes) -> None:
         self.cid = cid
         self.payload = payload
 
-    def __bytes__(self):
+    def __bytes__(self) -> bytes:
         return self.to_bytes()
 
-    def __str__(self):
+    def __str__(self) -> str:
         return f'{color("L2CAP", "green")} [CID={self.cid}]: {self.payload.hex()}'
 
 
@@ -188,10 +203,10 @@
 
     classes: Dict[int, Type[L2CAP_Control_Frame]] = {}
     code = 0
-    name = None
+    name: str
 
     @staticmethod
-    def from_bytes(pdu):
+    def from_bytes(pdu: bytes) -> L2CAP_Control_Frame:
         code = pdu[0]
 
         cls = L2CAP_Control_Frame.classes.get(code)
@@ -216,11 +231,11 @@
         return self
 
     @staticmethod
-    def code_name(code):
+    def code_name(code: int) -> str:
         return name_or_number(L2CAP_CONTROL_FRAME_NAMES, code)
 
     @staticmethod
-    def decode_configuration_options(data):
+    def decode_configuration_options(data: bytes) -> List[Tuple[int, bytes]]:
         options = []
         while len(data) >= 2:
             value_type = data[0]
@@ -232,7 +247,7 @@
         return options
 
     @staticmethod
-    def encode_configuration_options(options):
+    def encode_configuration_options(options: List[Tuple[int, bytes]]) -> bytes:
         return b''.join(
             [bytes([option[0], len(option[1])]) + option[1] for option in options]
         )
@@ -256,29 +271,30 @@
 
         return inner
 
-    def __init__(self, pdu=None, **kwargs):
+    def __init__(self, pdu=None, **kwargs) -> None:
         self.identifier = kwargs.get('identifier', 0)
-        if hasattr(self, 'fields') and kwargs:
-            HCI_Object.init_from_fields(self, self.fields, kwargs)
-        if pdu is None:
-            data = HCI_Object.dict_to_bytes(kwargs, self.fields)
-            pdu = (
-                bytes([self.code, self.identifier])
-                + struct.pack('<H', len(data))
-                + data
-            )
+        if hasattr(self, 'fields'):
+            if kwargs:
+                HCI_Object.init_from_fields(self, self.fields, kwargs)
+            if pdu is None:
+                data = HCI_Object.dict_to_bytes(kwargs, self.fields)
+                pdu = (
+                    bytes([self.code, self.identifier])
+                    + struct.pack('<H', len(data))
+                    + data
+                )
         self.pdu = pdu
 
     def init_from_bytes(self, pdu, offset):
         return HCI_Object.init_from_bytes(self, pdu, offset, self.fields)
 
-    def to_bytes(self):
+    def to_bytes(self) -> bytes:
         return self.pdu
 
-    def __bytes__(self):
+    def __bytes__(self) -> bytes:
         return self.to_bytes()
 
-    def __str__(self):
+    def __str__(self) -> str:
         result = f'{color(self.name, "yellow")} [ID={self.identifier}]'
         if fields := getattr(self, 'fields', None):
             result += ':\n' + HCI_Object.format_fields(self.__dict__, fields, '  ')
@@ -315,7 +331,7 @@
     }
 
     @staticmethod
-    def reason_name(reason):
+    def reason_name(reason: int) -> str:
         return name_or_number(L2CAP_Command_Reject.REASON_NAMES, reason)
 
 
@@ -343,7 +359,7 @@
     '''
 
     @staticmethod
-    def parse_psm(data, offset=0):
+    def parse_psm(data: bytes, offset: int = 0) -> Tuple[int, int]:
         psm_length = 2
         psm = data[offset] | data[offset + 1] << 8
 
@@ -355,7 +371,7 @@
         return offset + psm_length, psm
 
     @staticmethod
-    def serialize_psm(psm):
+    def serialize_psm(psm: int) -> bytes:
         serialized = struct.pack('<H', psm & 0xFFFF)
         psm >>= 16
         while psm:
@@ -405,7 +421,7 @@
     }
 
     @staticmethod
-    def result_name(result):
+    def result_name(result: int) -> str:
         return name_or_number(L2CAP_Connection_Response.RESULT_NAMES, result)
 
 
@@ -452,7 +468,7 @@
     }
 
     @staticmethod
-    def result_name(result):
+    def result_name(result: int) -> str:
         return name_or_number(L2CAP_Configure_Response.RESULT_NAMES, result)
 
 
@@ -529,7 +545,7 @@
     }
 
     @staticmethod
-    def info_type_name(info_type):
+    def info_type_name(info_type: int) -> str:
         return name_or_number(L2CAP_Information_Request.INFO_TYPE_NAMES, info_type)
 
 
@@ -556,7 +572,7 @@
     RESULT_NAMES = {SUCCESS: 'SUCCESS', NOT_SUPPORTED: 'NOT_SUPPORTED'}
 
     @staticmethod
-    def result_name(result):
+    def result_name(result: int) -> str:
         return name_or_number(L2CAP_Information_Response.RESULT_NAMES, result)
 
 
@@ -588,6 +604,8 @@
     (CODE 0x14)
     '''
 
+    source_cid: int
+
 
 # -----------------------------------------------------------------------------
 @L2CAP_Control_Frame.subclass(
@@ -640,7 +658,7 @@
     }
 
     @staticmethod
-    def result_name(result):
+    def result_name(result: int) -> str:
         return name_or_number(
             L2CAP_LE_Credit_Based_Connection_Response.RESULT_NAMES, result
         )
@@ -701,7 +719,22 @@
         WAIT_CONTROL_IND: 'WAIT_CONTROL_IND',
     }
 
-    def __init__(self, manager, connection, signaling_cid, psm, source_cid, mtu):
+    connection_result: Optional[asyncio.Future[None]]
+    disconnection_result: Optional[asyncio.Future[None]]
+    response: Optional[asyncio.Future[bytes]]
+    sink: Optional[Callable[[bytes], Any]]
+    state: int
+    connection: Connection
+
+    def __init__(
+        self,
+        manager: 'ChannelManager',
+        connection: Connection,
+        signaling_cid: int,
+        psm: int,
+        source_cid: int,
+        mtu: int,
+    ) -> None:
         super().__init__()
         self.manager = manager
         self.connection = connection
@@ -716,19 +749,19 @@
         self.disconnection_result = None
         self.sink = None
 
-    def change_state(self, new_state):
+    def change_state(self, new_state: int) -> None:
         logger.debug(
             f'{self} state change -> {color(Channel.STATE_NAMES[new_state], "cyan")}'
         )
         self.state = new_state
 
-    def send_pdu(self, pdu):
+    def send_pdu(self, pdu) -> None:
         self.manager.send_pdu(self.connection, self.destination_cid, pdu)
 
-    def send_control_frame(self, frame):
+    def send_control_frame(self, frame) -> None:
         self.manager.send_control_frame(self.connection, self.signaling_cid, frame)
 
-    async def send_request(self, request):
+    async def send_request(self, request) -> bytes:
         # Check that there isn't already a request pending
         if self.response:
             raise InvalidStateError('request already pending')
@@ -739,7 +772,7 @@
         self.send_pdu(request)
         return await self.response
 
-    def on_pdu(self, pdu):
+    def on_pdu(self, pdu) -> None:
         if self.response:
             self.response.set_result(pdu)
             self.response = None
@@ -751,7 +784,7 @@
                 color('received pdu without a pending request or sink', 'red')
             )
 
-    async def connect(self):
+    async def connect(self) -> None:
         if self.state != Channel.CLOSED:
             raise InvalidStateError('invalid state')
 
@@ -778,7 +811,7 @@
         finally:
             self.connection_result = None
 
-    async def disconnect(self):
+    async def disconnect(self) -> None:
         if self.state != Channel.OPEN:
             raise InvalidStateError('invalid state')
 
@@ -796,12 +829,12 @@
         self.disconnection_result = asyncio.get_running_loop().create_future()
         return await self.disconnection_result
 
-    def abort(self):
+    def abort(self) -> None:
         if self.state == self.OPEN:
             self.change_state(self.CLOSED)
             self.emit('close')
 
-    def send_configure_request(self):
+    def send_configure_request(self) -> None:
         options = L2CAP_Control_Frame.encode_configuration_options(
             [
                 (
@@ -819,7 +852,7 @@
             )
         )
 
-    def on_connection_request(self, request):
+    def on_connection_request(self, request) -> None:
         self.destination_cid = request.source_cid
         self.change_state(Channel.WAIT_CONNECT)
         self.send_control_frame(
@@ -858,7 +891,7 @@
             )
             self.connection_result = None
 
-    def on_configure_request(self, request):
+    def on_configure_request(self, request) -> None:
         if self.state not in (
             Channel.WAIT_CONFIG,
             Channel.WAIT_CONFIG_REQ,
@@ -896,7 +929,7 @@
         elif self.state == Channel.WAIT_CONFIG_REQ_RSP:
             self.change_state(Channel.WAIT_CONFIG_RSP)
 
-    def on_configure_response(self, response):
+    def on_configure_response(self, response) -> None:
         if response.result == L2CAP_Configure_Response.SUCCESS:
             if self.state == Channel.WAIT_CONFIG_REQ_RSP:
                 self.change_state(Channel.WAIT_CONFIG_REQ)
@@ -930,7 +963,7 @@
             )
             # TODO: decide how to fail gracefully
 
-    def on_disconnection_request(self, request):
+    def on_disconnection_request(self, request) -> None:
         if self.state in (Channel.OPEN, Channel.WAIT_DISCONNECT):
             self.send_control_frame(
                 L2CAP_Disconnection_Response(
@@ -945,7 +978,7 @@
         else:
             logger.warning(color('invalid state', 'red'))
 
-    def on_disconnection_response(self, response):
+    def on_disconnection_response(self, response) -> None:
         if self.state != Channel.WAIT_DISCONNECT:
             logger.warning(color('invalid state', 'red'))
             return
@@ -964,7 +997,7 @@
         self.emit('close')
         self.manager.on_channel_closed(self)
 
-    def __str__(self):
+    def __str__(self) -> str:
         return (
             f'Channel({self.source_cid}->{self.destination_cid}, '
             f'PSM={self.psm}, '
@@ -995,25 +1028,32 @@
         CONNECTION_ERROR: 'CONNECTION_ERROR',
     }
 
+    out_queue: Deque[bytes]
+    connection_result: Optional[asyncio.Future[LeConnectionOrientedChannel]]
+    disconnection_result: Optional[asyncio.Future[None]]
+    out_sdu: Optional[bytes]
+    state: int
+    connection: Connection
+
     @staticmethod
-    def state_name(state):
+    def state_name(state: int) -> str:
         return name_or_number(LeConnectionOrientedChannel.STATE_NAMES, state)
 
     def __init__(
         self,
-        manager,
-        connection,
-        le_psm,
-        source_cid,
-        destination_cid,
-        mtu,
-        mps,
-        credits,  # pylint: disable=redefined-builtin
-        peer_mtu,
-        peer_mps,
-        peer_credits,
-        connected,
-    ):
+        manager: 'ChannelManager',
+        connection: Connection,
+        le_psm: int,
+        source_cid: int,
+        destination_cid: int,
+        mtu: int,
+        mps: int,
+        credits: int,  # pylint: disable=redefined-builtin
+        peer_mtu: int,
+        peer_mps: int,
+        peer_credits: int,
+        connected: bool,
+    ) -> None:
         super().__init__()
         self.manager = manager
         self.connection = connection
@@ -1045,7 +1085,7 @@
         else:
             self.state = LeConnectionOrientedChannel.INIT
 
-    def change_state(self, new_state):
+    def change_state(self, new_state: int) -> None:
         logger.debug(
             f'{self} state change -> {color(self.state_name(new_state), "cyan")}'
         )
@@ -1056,13 +1096,13 @@
         elif new_state == self.DISCONNECTED:
             self.emit('close')
 
-    def send_pdu(self, pdu):
+    def send_pdu(self, pdu) -> None:
         self.manager.send_pdu(self.connection, self.destination_cid, pdu)
 
-    def send_control_frame(self, frame):
+    def send_control_frame(self, frame) -> None:
         self.manager.send_control_frame(self.connection, L2CAP_LE_SIGNALING_CID, frame)
 
-    async def connect(self):
+    async def connect(self) -> LeConnectionOrientedChannel:
         # Check that we're in the right state
         if self.state != self.INIT:
             raise InvalidStateError('not in a connectable state')
@@ -1090,7 +1130,7 @@
         # Wait for the connection to succeed or fail
         return await self.connection_result
 
-    async def disconnect(self):
+    async def disconnect(self) -> None:
         # Check that we're connected
         if self.state != self.CONNECTED:
             raise InvalidStateError('not connected')
@@ -1110,11 +1150,11 @@
         self.disconnection_result = asyncio.get_running_loop().create_future()
         return await self.disconnection_result
 
-    def abort(self):
+    def abort(self) -> None:
         if self.state == self.CONNECTED:
             self.change_state(self.DISCONNECTED)
 
-    def on_pdu(self, pdu):
+    def on_pdu(self, pdu) -> None:
         if self.sink is None:
             logger.warning('received pdu without a sink')
             return
@@ -1180,7 +1220,7 @@
         self.in_sdu = None
         self.in_sdu_length = 0
 
-    def on_connection_response(self, response):
+    def on_connection_response(self, response) -> None:
         # Look for a matching pending response result
         if self.connection_result is None:
             logger.warning(
@@ -1214,14 +1254,14 @@
         # Cleanup
         self.connection_result = None
 
-    def on_credits(self, credits):  # pylint: disable=redefined-builtin
+    def on_credits(self, credits: int) -> None:  # pylint: disable=redefined-builtin
         self.credits += credits
         logger.debug(f'received {credits} credits, total = {self.credits}')
 
         # Try to send more data if we have any queued up
         self.process_output()
 
-    def on_disconnection_request(self, request):
+    def on_disconnection_request(self, request) -> None:
         self.send_control_frame(
             L2CAP_Disconnection_Response(
                 identifier=request.identifier,
@@ -1232,7 +1272,7 @@
         self.change_state(self.DISCONNECTED)
         self.flush_output()
 
-    def on_disconnection_response(self, response):
+    def on_disconnection_response(self, response) -> None:
         if self.state != self.DISCONNECTING:
             logger.warning(color('invalid state', 'red'))
             return
@@ -1249,11 +1289,11 @@
             self.disconnection_result.set_result(None)
             self.disconnection_result = None
 
-    def flush_output(self):
+    def flush_output(self) -> None:
         self.out_queue.clear()
         self.out_sdu = None
 
-    def process_output(self):
+    def process_output(self) -> None:
         while self.credits > 0:
             if self.out_sdu is not None:
                 # Finish the current SDU
@@ -1296,7 +1336,7 @@
                 self.drained.set()
                 return
 
-    def write(self, data):
+    def write(self, data: bytes) -> None:
         if self.state != self.CONNECTED:
             logger.warning('not connected, dropping data')
             return
@@ -1311,18 +1351,18 @@
         # Send what we can
         self.process_output()
 
-    async def drain(self):
+    async def drain(self) -> None:
         await self.drained.wait()
 
-    def pause_reading(self):
+    def pause_reading(self) -> None:
         # TODO: not implemented yet
         pass
 
-    def resume_reading(self):
+    def resume_reading(self) -> None:
         # TODO: not implemented yet
         pass
 
-    def __str__(self):
+    def __str__(self) -> str:
         return (
             f'CoC({self.source_cid}->{self.destination_cid}, '
             f'State={self.state_name(self.state)}, '
@@ -1335,9 +1375,21 @@
 
 # -----------------------------------------------------------------------------
 class ChannelManager:
+    identifiers: Dict[int, int]
+    channels: Dict[int, Dict[int, Union[Channel, LeConnectionOrientedChannel]]]
+    servers: Dict[int, Callable[[Channel], Any]]
+    le_coc_channels: Dict[int, Dict[int, LeConnectionOrientedChannel]]
+    le_coc_servers: Dict[
+        int, Tuple[Callable[[LeConnectionOrientedChannel], Any], int, int, int]
+    ]
+    le_coc_requests: Dict[int, L2CAP_LE_Credit_Based_Connection_Request]
+    fixed_channels: Dict[int, Optional[Callable[[int, bytes], Any]]]
+
     def __init__(
-        self, extended_features=(), connectionless_mtu=L2CAP_DEFAULT_CONNECTIONLESS_MTU
-    ):
+        self,
+        extended_features: Iterable[int] = (),
+        connectionless_mtu: int = L2CAP_DEFAULT_CONNECTIONLESS_MTU,
+    ) -> None:
         self._host = None
         self.identifiers = {}  # Incrementing identifier values by connection
         self.channels = {}  # All channels, mapped by connection and source cid
@@ -1366,20 +1418,20 @@
         if host is not None:
             host.on('disconnection', self.on_disconnection)
 
-    def find_channel(self, connection_handle, cid):
+    def find_channel(self, connection_handle: int, cid: int):
         if connection_channels := self.channels.get(connection_handle):
             return connection_channels.get(cid)
 
         return None
 
-    def find_le_coc_channel(self, connection_handle, cid):
+    def find_le_coc_channel(self, connection_handle: int, cid: int):
         if connection_channels := self.le_coc_channels.get(connection_handle):
             return connection_channels.get(cid)
 
         return None
 
     @staticmethod
-    def find_free_br_edr_cid(channels):
+    def find_free_br_edr_cid(channels: Iterable[int]) -> int:
         # Pick the smallest valid CID that's not already in the list
         # (not necessarily the most efficient algorithm, but the list of CID is
         # very small in practice)
@@ -1392,7 +1444,7 @@
         raise RuntimeError('no free CID available')
 
     @staticmethod
-    def find_free_le_cid(channels):
+    def find_free_le_cid(channels: Iterable[int]) -> int:
         # Pick the smallest valid CID that's not already in the list
         # (not necessarily the most efficient algorithm, but the list of CID is
         # very small in practice)
@@ -1405,7 +1457,7 @@
         raise RuntimeError('no free CID')
 
     @staticmethod
-    def check_le_coc_parameters(max_credits, mtu, mps):
+    def check_le_coc_parameters(max_credits: int, mtu: int, mps: int) -> None:
         if (
             max_credits < 1
             or max_credits > L2CAP_LE_CREDIT_BASED_CONNECTION_MAX_CREDITS
@@ -1419,19 +1471,21 @@
         ):
             raise ValueError('MPS out of range')
 
-    def next_identifier(self, connection):
+    def next_identifier(self, connection: Connection) -> int:
         identifier = (self.identifiers.setdefault(connection.handle, 0) + 1) % 256
         self.identifiers[connection.handle] = identifier
         return identifier
 
-    def register_fixed_channel(self, cid, handler):
+    def register_fixed_channel(
+        self, cid: int, handler: Callable[[int, bytes], Any]
+    ) -> None:
         self.fixed_channels[cid] = handler
 
-    def deregister_fixed_channel(self, cid):
+    def deregister_fixed_channel(self, cid: int) -> None:
         if cid in self.fixed_channels:
             del self.fixed_channels[cid]
 
-    def register_server(self, psm, server):
+    def register_server(self, psm: int, server: Callable[[Channel], Any]) -> int:
         if psm == 0:
             # Find a free PSM
             for candidate in range(
@@ -1465,12 +1519,12 @@
 
     def register_le_coc_server(
         self,
-        psm,
-        server,
-        max_credits=L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_INITIAL_CREDITS,
-        mtu=L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MTU,
-        mps=L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MPS,
-    ):
+        psm: int,
+        server: Callable[[LeConnectionOrientedChannel], Any],
+        max_credits: int = L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_INITIAL_CREDITS,
+        mtu: int = L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MTU,
+        mps: int = L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MPS,
+    ) -> int:
         self.check_le_coc_parameters(max_credits, mtu, mps)
 
         if psm == 0:
@@ -1498,7 +1552,7 @@
 
         return psm
 
-    def on_disconnection(self, connection_handle, _reason):
+    def on_disconnection(self, connection_handle: int, _reason: int) -> None:
         logger.debug(f'disconnection from {connection_handle}, cleaning up channels')
         if connection_handle in self.channels:
             for _, channel in self.channels[connection_handle].items():
@@ -1511,7 +1565,7 @@
         if connection_handle in self.identifiers:
             del self.identifiers[connection_handle]
 
-    def send_pdu(self, connection, cid, pdu):
+    def send_pdu(self, connection, cid: int, pdu) -> None:
         pdu_str = pdu.hex() if isinstance(pdu, bytes) else str(pdu)
         logger.debug(
             f'{color(">>> Sending L2CAP PDU", "blue")} '
@@ -1520,14 +1574,16 @@
         )
         self.host.send_l2cap_pdu(connection.handle, cid, bytes(pdu))
 
-    def on_pdu(self, connection, cid, pdu):
+    def on_pdu(self, connection: Connection, cid: int, pdu) -> None:
         if cid in (L2CAP_SIGNALING_CID, L2CAP_LE_SIGNALING_CID):
             # Parse the L2CAP payload into a Control Frame object
             control_frame = L2CAP_Control_Frame.from_bytes(pdu)
 
             self.on_control_frame(connection, cid, control_frame)
         elif cid in self.fixed_channels:
-            self.fixed_channels[cid](connection.handle, pdu)
+            handler = self.fixed_channels[cid]
+            assert handler is not None
+            handler(connection.handle, pdu)
         else:
             if (channel := self.find_channel(connection.handle, cid)) is None:
                 logger.warning(
@@ -1539,7 +1595,9 @@
 
             channel.on_pdu(pdu)
 
-    def send_control_frame(self, connection, cid, control_frame):
+    def send_control_frame(
+        self, connection: Connection, cid: int, control_frame
+    ) -> None:
         logger.debug(
             f'{color(">>> Sending L2CAP Signaling Control Frame", "blue")} '
             f'on connection [0x{connection.handle:04X}] (CID={cid}) '
@@ -1547,7 +1605,7 @@
         )
         self.host.send_l2cap_pdu(connection.handle, cid, bytes(control_frame))
 
-    def on_control_frame(self, connection, cid, control_frame):
+    def on_control_frame(self, connection: Connection, cid: int, control_frame) -> None:
         logger.debug(
             f'{color("<<< Received L2CAP Signaling Control Frame", "green")} '
             f'on connection [0x{connection.handle:04X}] (CID={cid}) '
@@ -1584,10 +1642,14 @@
                 ),
             )
 
-    def on_l2cap_command_reject(self, _connection, _cid, packet):
+    def on_l2cap_command_reject(
+        self, _connection: Connection, _cid: int, packet
+    ) -> None:
         logger.warning(f'{color("!!! Command rejected:", "red")} {packet.reason}')
 
-    def on_l2cap_connection_request(self, connection, cid, request):
+    def on_l2cap_connection_request(
+        self, connection: Connection, cid: int, request
+    ) -> None:
         # Check if there's a server for this PSM
         server = self.servers.get(request.psm)
         if server:
@@ -1639,7 +1701,9 @@
                 ),
             )
 
-    def on_l2cap_connection_response(self, connection, cid, response):
+    def on_l2cap_connection_response(
+        self, connection: Connection, cid: int, response
+    ) -> None:
         if (
             channel := self.find_channel(connection.handle, response.source_cid)
         ) is None:
@@ -1654,7 +1718,9 @@
 
         channel.on_connection_response(response)
 
-    def on_l2cap_configure_request(self, connection, cid, request):
+    def on_l2cap_configure_request(
+        self, connection: Connection, cid: int, request
+    ) -> None:
         if (
             channel := self.find_channel(connection.handle, request.destination_cid)
         ) is None:
@@ -1669,7 +1735,9 @@
 
         channel.on_configure_request(request)
 
-    def on_l2cap_configure_response(self, connection, cid, response):
+    def on_l2cap_configure_response(
+        self, connection: Connection, cid: int, response
+    ) -> None:
         if (
             channel := self.find_channel(connection.handle, response.source_cid)
         ) is None:
@@ -1684,7 +1752,9 @@
 
         channel.on_configure_response(response)
 
-    def on_l2cap_disconnection_request(self, connection, cid, request):
+    def on_l2cap_disconnection_request(
+        self, connection: Connection, cid: int, request
+    ) -> None:
         if (
             channel := self.find_channel(connection.handle, request.destination_cid)
         ) is None:
@@ -1699,7 +1769,9 @@
 
         channel.on_disconnection_request(request)
 
-    def on_l2cap_disconnection_response(self, connection, cid, response):
+    def on_l2cap_disconnection_response(
+        self, connection: Connection, cid: int, response
+    ) -> None:
         if (
             channel := self.find_channel(connection.handle, response.source_cid)
         ) is None:
@@ -1714,7 +1786,7 @@
 
         channel.on_disconnection_response(response)
 
-    def on_l2cap_echo_request(self, connection, cid, request):
+    def on_l2cap_echo_request(self, connection: Connection, cid: int, request) -> None:
         logger.debug(f'<<< Echo request: data={request.data.hex()}')
         self.send_control_frame(
             connection,
@@ -1722,11 +1794,15 @@
             L2CAP_Echo_Response(identifier=request.identifier, data=request.data),
         )
 
-    def on_l2cap_echo_response(self, _connection, _cid, response):
+    def on_l2cap_echo_response(
+        self, _connection: Connection, _cid: int, response
+    ) -> None:
         logger.debug(f'<<< Echo response: data={response.data.hex()}')
         # TODO notify listeners
 
-    def on_l2cap_information_request(self, connection, cid, request):
+    def on_l2cap_information_request(
+        self, connection: Connection, cid: int, request
+    ) -> None:
         if request.info_type == L2CAP_Information_Request.CONNECTIONLESS_MTU:
             result = L2CAP_Information_Response.SUCCESS
             data = self.connectionless_mtu.to_bytes(2, 'little')
@@ -1750,7 +1826,9 @@
             ),
         )
 
-    def on_l2cap_connection_parameter_update_request(self, connection, cid, request):
+    def on_l2cap_connection_parameter_update_request(
+        self, connection: Connection, cid: int, request
+    ):
         if connection.role == BT_CENTRAL_ROLE:
             self.send_control_frame(
                 connection,
@@ -1769,7 +1847,7 @@
                     supervision_timeout=request.timeout,
                     min_ce_length=0,
                     max_ce_length=0,
-                )
+                )  # type: ignore[call-arg]
             )
         else:
             self.send_control_frame(
@@ -1781,11 +1859,15 @@
                 ),
             )
 
-    def on_l2cap_connection_parameter_update_response(self, connection, cid, response):
+    def on_l2cap_connection_parameter_update_response(
+        self, connection: Connection, cid: int, response
+    ) -> None:
         # TODO: check response
         pass
 
-    def on_l2cap_le_credit_based_connection_request(self, connection, cid, request):
+    def on_l2cap_le_credit_based_connection_request(
+        self, connection: Connection, cid: int, request
+    ) -> None:
         if request.le_psm in self.le_coc_servers:
             (server, max_credits, mtu, mps) = self.le_coc_servers[request.le_psm]
 
@@ -1887,7 +1969,9 @@
                 ),
             )
 
-    def on_l2cap_le_credit_based_connection_response(self, connection, _cid, response):
+    def on_l2cap_le_credit_based_connection_response(
+        self, connection: Connection, _cid: int, response
+    ) -> None:
         # Find the pending request by identifier
         request = self.le_coc_requests.get(response.identifier)
         if request is None:
@@ -1910,7 +1994,9 @@
         # Process the response
         channel.on_connection_response(response)
 
-    def on_l2cap_le_flow_control_credit(self, connection, _cid, credit):
+    def on_l2cap_le_flow_control_credit(
+        self, connection: Connection, _cid: int, credit
+    ) -> None:
         channel = self.find_le_coc_channel(connection.handle, credit.cid)
         if channel is None:
             logger.warning(f'received credits for an unknown channel (cid={credit.cid}')
@@ -1918,13 +2004,15 @@
 
         channel.on_credits(credit.credits)
 
-    def on_channel_closed(self, channel):
+    def on_channel_closed(self, channel: Channel) -> None:
         connection_channels = self.channels.get(channel.connection.handle)
         if connection_channels:
             if channel.source_cid in connection_channels:
                 del connection_channels[channel.source_cid]
 
-    async def open_le_coc(self, connection, psm, max_credits, mtu, mps):
+    async def open_le_coc(
+        self, connection: Connection, psm: int, max_credits: int, mtu: int, mps: int
+    ) -> LeConnectionOrientedChannel:
         self.check_le_coc_parameters(max_credits, mtu, mps)
 
         # Find a free CID for the new channel
@@ -1965,7 +2053,7 @@
 
         return channel
 
-    async def connect(self, connection, psm):
+    async def connect(self, connection: Connection, psm: int) -> Channel:
         # NOTE: this implementation hard-codes BR/EDR
 
         # Find a free CID for a new channel
diff --git a/bumble/pairing.py b/bumble/pairing.py
index ab356ee..877b739 100644
--- a/bumble/pairing.py
+++ b/bumble/pairing.py
@@ -19,6 +19,7 @@
 from typing import Optional, Tuple
 
 from .hci import (
+    Address,
     HCI_NO_INPUT_NO_OUTPUT_IO_CAPABILITY,
     HCI_DISPLAY_ONLY_IO_CAPABILITY,
     HCI_DISPLAY_YES_NO_IO_CAPABILITY,
@@ -168,21 +169,28 @@
 class PairingConfig:
     """Configuration for the Pairing protocol."""
 
+    class AddressType(enum.IntEnum):
+        PUBLIC = Address.PUBLIC_DEVICE_ADDRESS
+        RANDOM = Address.RANDOM_DEVICE_ADDRESS
+
     def __init__(
         self,
         sc: bool = True,
         mitm: bool = True,
         bonding: bool = True,
         delegate: Optional[PairingDelegate] = None,
+        identity_address_type: Optional[AddressType] = None,
     ) -> None:
         self.sc = sc
         self.mitm = mitm
         self.bonding = bonding
         self.delegate = delegate or PairingDelegate()
+        self.identity_address_type = identity_address_type
 
     def __str__(self) -> str:
         return (
             f'PairingConfig(sc={self.sc}, '
             f'mitm={self.mitm}, bonding={self.bonding}, '
+            f'identity_address_type={self.identity_address_type}, '
             f'delegate[{self.delegate.io_capability}])'
         )
diff --git a/bumble/pandora/device.py b/bumble/pandora/device.py
index a4403b6..9173900 100644
--- a/bumble/pandora/device.py
+++ b/bumble/pandora/device.py
@@ -34,6 +34,10 @@
 from typing import Any, Dict, List, Optional
 
 
+# Default rootcanal HCI TCP address
+ROOTCANAL_HCI_ADDRESS = "localhost:6402"
+
+
 class PandoraDevice:
     """
     Small wrapper around a Bumble device and it's HCI transport.
@@ -53,7 +57,9 @@
     def __init__(self, config: Dict[str, Any]) -> None:
         self.config = config
         self.device = _make_device(config)
-        self._hci_name = config.get('transport', '')
+        self._hci_name = config.get(
+            'transport', f"tcp-client:{config.get('tcp', ROOTCANAL_HCI_ADDRESS)}"
+        )
         self._hci = None
 
     @property
diff --git a/bumble/pandora/host.py b/bumble/pandora/host.py
index 63b295d..9e6e4b5 100644
--- a/bumble/pandora/host.py
+++ b/bumble/pandora/host.py
@@ -43,7 +43,8 @@
     HCI_REMOTE_USER_TERMINATED_CONNECTION_ERROR,
     Address,
 )
-from google.protobuf import any_pb2, empty_pb2  # pytype: disable=pyi-error
+from google.protobuf import any_pb2  # pytype: disable=pyi-error
+from google.protobuf import empty_pb2  # pytype: disable=pyi-error
 from pandora.host_grpc_aio import HostServicer
 from pandora.host_pb2 import (
     NOT_CONNECTABLE,
@@ -111,7 +112,7 @@
     async def FactoryReset(
         self, request: empty_pb2.Empty, context: grpc.ServicerContext
     ) -> empty_pb2.Empty:
-        self.log.info('FactoryReset')
+        self.log.debug('FactoryReset')
 
         # delete all bonds
         if self.device.keystore is not None:
@@ -125,7 +126,7 @@
     async def Reset(
         self, request: empty_pb2.Empty, context: grpc.ServicerContext
     ) -> empty_pb2.Empty:
-        self.log.info('Reset')
+        self.log.debug('Reset')
 
         # clear service.
         self.waited_connections.clear()
@@ -138,7 +139,7 @@
     async def ReadLocalAddress(
         self, request: empty_pb2.Empty, context: grpc.ServicerContext
     ) -> ReadLocalAddressResponse:
-        self.log.info('ReadLocalAddress')
+        self.log.debug('ReadLocalAddress')
         return ReadLocalAddressResponse(
             address=bytes(reversed(bytes(self.device.public_address)))
         )
@@ -151,7 +152,7 @@
         address = Address(
             bytes(reversed(request.address)), address_type=Address.PUBLIC_DEVICE_ADDRESS
         )
-        self.log.info(f"Connect to {address}")
+        self.log.debug(f"Connect to {address}")
 
         try:
             connection = await self.device.connect(
@@ -166,7 +167,7 @@
                 return ConnectResponse(connection_already_exists=empty_pb2.Empty())
             raise e
 
-        self.log.info(f"Connect to {address} done (handle={connection.handle})")
+        self.log.debug(f"Connect to {address} done (handle={connection.handle})")
 
         cookie = any_pb2.Any(value=connection.handle.to_bytes(4, 'big'))
         return ConnectResponse(connection=Connection(cookie=cookie))
@@ -185,7 +186,7 @@
         if address in (Address.NIL, Address.ANY):
             raise ValueError('Invalid address')
 
-        self.log.info(f"WaitConnection from {address}...")
+        self.log.debug(f"WaitConnection from {address}...")
 
         connection = self.device.find_connection_by_bd_addr(
             address, transport=BT_BR_EDR_TRANSPORT
@@ -200,7 +201,7 @@
         # save connection has waited and respond.
         self.waited_connections.add(id(connection))
 
-        self.log.info(
+        self.log.debug(
             f"WaitConnection from {address} done (handle={connection.handle})"
         )
 
@@ -215,7 +216,7 @@
         if address in (Address.NIL, Address.ANY):
             raise ValueError('Invalid address')
 
-        self.log.info(f"ConnectLE to {address}...")
+        self.log.debug(f"ConnectLE to {address}...")
 
         try:
             connection = await self.device.connect(
@@ -232,7 +233,7 @@
                 return ConnectLEResponse(connection_already_exists=empty_pb2.Empty())
             raise e
 
-        self.log.info(f"ConnectLE to {address} done (handle={connection.handle})")
+        self.log.debug(f"ConnectLE to {address} done (handle={connection.handle})")
 
         cookie = any_pb2.Any(value=connection.handle.to_bytes(4, 'big'))
         return ConnectLEResponse(connection=Connection(cookie=cookie))
@@ -242,12 +243,12 @@
         self, request: DisconnectRequest, context: grpc.ServicerContext
     ) -> empty_pb2.Empty:
         connection_handle = int.from_bytes(request.connection.cookie.value, 'big')
-        self.log.info(f"Disconnect: {connection_handle}")
+        self.log.debug(f"Disconnect: {connection_handle}")
 
-        self.log.info("Disconnecting...")
+        self.log.debug("Disconnecting...")
         if connection := self.device.lookup_connection(connection_handle):
             await connection.disconnect(HCI_REMOTE_USER_TERMINATED_CONNECTION_ERROR)
-        self.log.info("Disconnected")
+        self.log.debug("Disconnected")
 
         return empty_pb2.Empty()
 
@@ -256,7 +257,7 @@
         self, request: WaitDisconnectionRequest, context: grpc.ServicerContext
     ) -> empty_pb2.Empty:
         connection_handle = int.from_bytes(request.connection.cookie.value, 'big')
-        self.log.info(f"WaitDisconnection: {connection_handle}")
+        self.log.debug(f"WaitDisconnection: {connection_handle}")
 
         if connection := self.device.lookup_connection(connection_handle):
             disconnection_future: asyncio.Future[
@@ -269,7 +270,7 @@
             connection.on('disconnection', on_disconnection)
             try:
                 await disconnection_future
-                self.log.info("Disconnected")
+                self.log.debug("Disconnected")
             finally:
                 connection.remove_listener('disconnection', on_disconnection)  # type: ignore
 
@@ -377,7 +378,7 @@
         try:
             while True:
                 if not self.device.is_advertising:
-                    self.log.info('Advertise')
+                    self.log.debug('Advertise')
                     await self.device.start_advertising(
                         target=target,
                         advertising_type=advertising_type,
@@ -392,10 +393,10 @@
                     bumble.device.Connection
                 ] = asyncio.get_running_loop().create_future()
 
-                self.log.info('Wait for LE connection...')
+                self.log.debug('Wait for LE connection...')
                 connection = await pending_connection
 
-                self.log.info(
+                self.log.debug(
                     f"Advertise: Connected to {connection.peer_address} (handle={connection.handle})"
                 )
 
@@ -409,7 +410,7 @@
                 self.device.remove_listener('connection', on_connection)  # type: ignore
 
             try:
-                self.log.info('Stop advertising')
+                self.log.debug('Stop advertising')
                 await self.device.abort_on('flush', self.device.stop_advertising())
             except:
                 pass
@@ -422,7 +423,7 @@
         if request.phys:
             raise NotImplementedError("TODO: add support for `request.phys`")
 
-        self.log.info('Scan')
+        self.log.debug('Scan')
 
         scan_queue: asyncio.Queue[Advertisement] = asyncio.Queue()
         handler = self.device.on('advertisement', scan_queue.put_nowait)
@@ -469,7 +470,7 @@
         finally:
             self.device.remove_listener('advertisement', handler)  # type: ignore
             try:
-                self.log.info('Stop scanning')
+                self.log.debug('Stop scanning')
                 await self.device.abort_on('flush', self.device.stop_scanning())
             except:
                 pass
@@ -478,7 +479,7 @@
     async def Inquiry(
         self, request: empty_pb2.Empty, context: grpc.ServicerContext
     ) -> AsyncGenerator[InquiryResponse, None]:
-        self.log.info('Inquiry')
+        self.log.debug('Inquiry')
 
         inquiry_queue: asyncio.Queue[
             Optional[Tuple[Address, int, AdvertisingData, int]]
@@ -509,7 +510,7 @@
             self.device.remove_listener('inquiry_complete', complete_handler)  # type: ignore
             self.device.remove_listener('inquiry_result', result_handler)  # type: ignore
             try:
-                self.log.info('Stop inquiry')
+                self.log.debug('Stop inquiry')
                 await self.device.abort_on('flush', self.device.stop_discovery())
             except:
                 pass
@@ -518,7 +519,7 @@
     async def SetDiscoverabilityMode(
         self, request: SetDiscoverabilityModeRequest, context: grpc.ServicerContext
     ) -> empty_pb2.Empty:
-        self.log.info("SetDiscoverabilityMode")
+        self.log.debug("SetDiscoverabilityMode")
         await self.device.set_discoverable(request.mode != NOT_DISCOVERABLE)
         return empty_pb2.Empty()
 
@@ -526,7 +527,7 @@
     async def SetConnectabilityMode(
         self, request: SetConnectabilityModeRequest, context: grpc.ServicerContext
     ) -> empty_pb2.Empty:
-        self.log.info("SetConnectabilityMode")
+        self.log.debug("SetConnectabilityMode")
         await self.device.set_connectable(request.mode != NOT_CONNECTABLE)
         return empty_pb2.Empty()
 
diff --git a/bumble/pandora/security.py b/bumble/pandora/security.py
index fee1b7a..9f98f3f 100644
--- a/bumble/pandora/security.py
+++ b/bumble/pandora/security.py
@@ -29,12 +29,9 @@
 from bumble.hci import HCI_Error
 from bumble.pairing import PairingConfig, PairingDelegate as BasePairingDelegate
 from contextlib import suppress
-from google.protobuf import (
-    any_pb2,
-    empty_pb2,
-    wrappers_pb2,
-)  # pytype: disable=pyi-error
-from google.protobuf.wrappers_pb2 import BoolValue  # pytype: disable=pyi-error
+from google.protobuf import any_pb2  # pytype: disable=pyi-error
+from google.protobuf import empty_pb2  # pytype: disable=pyi-error
+from google.protobuf import wrappers_pb2  # pytype: disable=pyi-error
 from pandora.host_pb2 import Connection
 from pandora.security_grpc_aio import SecurityServicer, SecurityStorageServicer
 from pandora.security_pb2 import (
@@ -102,7 +99,7 @@
         return ev
 
     async def confirm(self, auto: bool = False) -> bool:
-        self.log.info(
+        self.log.debug(
             f"Pairing event: `just_works` (io_capability: {self.io_capability})"
         )
 
@@ -117,7 +114,7 @@
         return answer.confirm
 
     async def compare_numbers(self, number: int, digits: int = 6) -> bool:
-        self.log.info(
+        self.log.debug(
             f"Pairing event: `numeric_comparison` (io_capability: {self.io_capability})"
         )
 
@@ -132,7 +129,7 @@
         return answer.confirm
 
     async def get_number(self) -> Optional[int]:
-        self.log.info(
+        self.log.debug(
             f"Pairing event: `passkey_entry_request` (io_capability: {self.io_capability})"
         )
 
@@ -149,7 +146,7 @@
         return answer.passkey
 
     async def get_string(self, max_length: int) -> Optional[str]:
-        self.log.info(
+        self.log.debug(
             f"Pairing event: `pin_code_request` (io_capability: {self.io_capability})"
         )
 
@@ -180,7 +177,7 @@
         ):
             return
 
-        self.log.info(
+        self.log.debug(
             f"Pairing event: `passkey_entry_notification` (io_capability: {self.io_capability})"
         )
 
@@ -250,7 +247,7 @@
     async def OnPairing(
         self, request: AsyncIterator[PairingEventAnswer], context: grpc.ServicerContext
     ) -> AsyncGenerator[PairingEvent, None]:
-        self.log.info('OnPairing')
+        self.log.debug('OnPairing')
 
         if self.event_queue is not None:
             raise RuntimeError('already streaming pairing events')
@@ -276,7 +273,7 @@
         self, request: SecureRequest, context: grpc.ServicerContext
     ) -> SecureResponse:
         connection_handle = int.from_bytes(request.connection.cookie.value, 'big')
-        self.log.info(f"Secure: {connection_handle}")
+        self.log.debug(f"Secure: {connection_handle}")
 
         connection = self.device.lookup_connection(connection_handle)
         assert connection
@@ -294,7 +291,7 @@
         # trigger pairing if needed
         if self.need_pairing(connection, level):
             try:
-                self.log.info('Pair...')
+                self.log.debug('Pair...')
 
                 if (
                     connection.transport == BT_LE_TRANSPORT
@@ -312,7 +309,7 @@
                 else:
                     await connection.pair()
 
-                self.log.info('Paired')
+                self.log.debug('Paired')
             except asyncio.CancelledError:
                 self.log.warning("Connection died during encryption")
                 return SecureResponse(connection_died=empty_pb2.Empty())
@@ -323,9 +320,9 @@
         # trigger authentication if needed
         if self.need_authentication(connection, level):
             try:
-                self.log.info('Authenticate...')
+                self.log.debug('Authenticate...')
                 await connection.authenticate()
-                self.log.info('Authenticated')
+                self.log.debug('Authenticated')
             except asyncio.CancelledError:
                 self.log.warning("Connection died during authentication")
                 return SecureResponse(connection_died=empty_pb2.Empty())
@@ -336,9 +333,9 @@
         # trigger encryption if needed
         if self.need_encryption(connection, level):
             try:
-                self.log.info('Encrypt...')
+                self.log.debug('Encrypt...')
                 await connection.encrypt()
-                self.log.info('Encrypted')
+                self.log.debug('Encrypted')
             except asyncio.CancelledError:
                 self.log.warning("Connection died during encryption")
                 return SecureResponse(connection_died=empty_pb2.Empty())
@@ -356,7 +353,7 @@
         self, request: WaitSecurityRequest, context: grpc.ServicerContext
     ) -> WaitSecurityResponse:
         connection_handle = int.from_bytes(request.connection.cookie.value, 'big')
-        self.log.info(f"WaitSecurity: {connection_handle}")
+        self.log.debug(f"WaitSecurity: {connection_handle}")
 
         connection = self.device.lookup_connection(connection_handle)
         assert connection
@@ -393,7 +390,7 @@
 
         def set_failure(name: str) -> Callable[..., None]:
             def wrapper(*args: Any) -> None:
-                self.log.info(f'Wait for security: error `{name}`: {args}')
+                self.log.debug(f'Wait for security: error `{name}`: {args}')
                 wait_for_security.set_result(name)
 
             return wrapper
@@ -401,13 +398,13 @@
         def try_set_success(*_: Any) -> None:
             assert connection
             if self.reached_security_level(connection, level):
-                self.log.info('Wait for security: done')
+                self.log.debug('Wait for security: done')
                 wait_for_security.set_result('success')
 
         def on_encryption_change(*_: Any) -> None:
             assert connection
             if self.reached_security_level(connection, level):
-                self.log.info('Wait for security: done')
+                self.log.debug('Wait for security: done')
                 wait_for_security.set_result('success')
             elif (
                 connection.transport == BT_BR_EDR_TRANSPORT
@@ -435,7 +432,7 @@
         if self.reached_security_level(connection, level):
             return WaitSecurityResponse(success=empty_pb2.Empty())
 
-        self.log.info('Wait for security...')
+        self.log.debug('Wait for security...')
         kwargs = {}
         kwargs[await wait_for_security] = empty_pb2.Empty()
 
@@ -445,12 +442,12 @@
 
         # wait for `authenticate` to finish if any
         if authenticate_task is not None:
-            self.log.info('Wait for authentication...')
+            self.log.debug('Wait for authentication...')
             try:
                 await authenticate_task  # type: ignore
             except:
                 pass
-            self.log.info('Authenticated')
+            self.log.debug('Authenticated')
 
         return WaitSecurityResponse(**kwargs)
 
@@ -506,21 +503,21 @@
         self, request: IsBondedRequest, context: grpc.ServicerContext
     ) -> wrappers_pb2.BoolValue:
         address = utils.address_from_request(request, request.WhichOneof("address"))
-        self.log.info(f"IsBonded: {address}")
+        self.log.debug(f"IsBonded: {address}")
 
         if self.device.keystore is not None:
             is_bonded = await self.device.keystore.get(str(address)) is not None
         else:
             is_bonded = False
 
-        return BoolValue(value=is_bonded)
+        return wrappers_pb2.BoolValue(value=is_bonded)
 
     @utils.rpc
     async def DeleteBond(
         self, request: DeleteBondRequest, context: grpc.ServicerContext
     ) -> empty_pb2.Empty:
         address = utils.address_from_request(request, request.WhichOneof("address"))
-        self.log.info(f"DeleteBond: {address}")
+        self.log.debug(f"DeleteBond: {address}")
 
         if self.device.keystore is not None:
             with suppress(KeyError):
diff --git a/bumble/rfcomm.py b/bumble/rfcomm.py
index 71be8dc..0176a78 100644
--- a/bumble/rfcomm.py
+++ b/bumble/rfcomm.py
@@ -19,8 +19,9 @@
 import asyncio
 
 from pyee import EventEmitter
+from typing import Optional, Tuple, Callable, Dict, Union
 
-from . import core
+from . import core, l2cap
 from .colors import color
 from .core import BT_BR_EDR_TRANSPORT, InvalidStateError, ProtocolError
 
@@ -105,7 +106,7 @@
 
 
 # -----------------------------------------------------------------------------
-def compute_fcs(buffer):
+def compute_fcs(buffer: bytes) -> int:
     result = 0xFF
     for byte in buffer:
         result = CRC_TABLE[result ^ byte]
@@ -114,7 +115,15 @@
 
 # -----------------------------------------------------------------------------
 class RFCOMM_Frame:
-    def __init__(self, frame_type, c_r, dlci, p_f, information=b'', with_credits=False):
+    def __init__(
+        self,
+        frame_type: int,
+        c_r: int,
+        dlci: int,
+        p_f: int,
+        information: bytes = b'',
+        with_credits: bool = False,
+    ) -> None:
         self.type = frame_type
         self.c_r = c_r
         self.dlci = dlci
@@ -136,11 +145,11 @@
         else:
             self.fcs = compute_fcs(bytes([self.address, self.control]) + self.length)
 
-    def type_name(self):
+    def type_name(self) -> str:
         return RFCOMM_FRAME_TYPE_NAMES[self.type]
 
     @staticmethod
-    def parse_mcc(data):
+    def parse_mcc(data) -> Tuple[int, int, bytes]:
         mcc_type = data[0] >> 2
         c_r = (data[0] >> 1) & 1
         length = data[1]
@@ -154,36 +163,36 @@
         return (mcc_type, c_r, value)
 
     @staticmethod
-    def make_mcc(mcc_type, c_r, data):
+    def make_mcc(mcc_type: int, c_r: int, data: bytes) -> bytes:
         return (
             bytes([(mcc_type << 2 | c_r << 1 | 1) & 0xFF, (len(data) & 0x7F) << 1 | 1])
             + data
         )
 
     @staticmethod
-    def sabm(c_r, dlci):
+    def sabm(c_r: int, dlci: int):
         return RFCOMM_Frame(RFCOMM_SABM_FRAME, c_r, dlci, 1)
 
     @staticmethod
-    def ua(c_r, dlci):
+    def ua(c_r: int, dlci: int):
         return RFCOMM_Frame(RFCOMM_UA_FRAME, c_r, dlci, 1)
 
     @staticmethod
-    def dm(c_r, dlci):
+    def dm(c_r: int, dlci: int):
         return RFCOMM_Frame(RFCOMM_DM_FRAME, c_r, dlci, 1)
 
     @staticmethod
-    def disc(c_r, dlci):
+    def disc(c_r: int, dlci: int):
         return RFCOMM_Frame(RFCOMM_DISC_FRAME, c_r, dlci, 1)
 
     @staticmethod
-    def uih(c_r, dlci, information, p_f=0):
+    def uih(c_r: int, dlci: int, information: bytes, p_f: int = 0):
         return RFCOMM_Frame(
             RFCOMM_UIH_FRAME, c_r, dlci, p_f, information, with_credits=(p_f == 1)
         )
 
     @staticmethod
-    def from_bytes(data):
+    def from_bytes(data: bytes):
         # Extract fields
         dlci = (data[0] >> 2) & 0x3F
         c_r = (data[0] >> 1) & 0x01
@@ -227,15 +236,23 @@
 
 # -----------------------------------------------------------------------------
 class RFCOMM_MCC_PN:
+    dlci: int
+    cl: int
+    priority: int
+    ack_timer: int
+    max_frame_size: int
+    max_retransmissions: int
+    window_size: int
+
     def __init__(
         self,
-        dlci,
-        cl,
-        priority,
-        ack_timer,
-        max_frame_size,
-        max_retransmissions,
-        window_size,
+        dlci: int,
+        cl: int,
+        priority: int,
+        ack_timer: int,
+        max_frame_size: int,
+        max_retransmissions: int,
+        window_size: int,
     ):
         self.dlci = dlci
         self.cl = cl
@@ -246,7 +263,7 @@
         self.window_size = window_size
 
     @staticmethod
-    def from_bytes(data):
+    def from_bytes(data: bytes):
         return RFCOMM_MCC_PN(
             dlci=data[0],
             cl=data[1],
@@ -285,7 +302,14 @@
 
 # -----------------------------------------------------------------------------
 class RFCOMM_MCC_MSC:
-    def __init__(self, dlci, fc, rtc, rtr, ic, dv):
+    dlci: int
+    fc: int
+    rtc: int
+    rtr: int
+    ic: int
+    dv: int
+
+    def __init__(self, dlci: int, fc: int, rtc: int, rtr: int, ic: int, dv: int):
         self.dlci = dlci
         self.fc = fc
         self.rtc = rtc
@@ -294,7 +318,7 @@
         self.dv = dv
 
     @staticmethod
-    def from_bytes(data):
+    def from_bytes(data: bytes):
         return RFCOMM_MCC_MSC(
             dlci=data[0] >> 2,
             fc=data[1] >> 1 & 1,
@@ -347,7 +371,12 @@
         RESET: 'RESET',
     }
 
-    def __init__(self, multiplexer, dlci, max_frame_size, initial_tx_credits):
+    connection_result: Optional[asyncio.Future]
+    sink: Optional[Callable[[bytes], None]]
+
+    def __init__(
+        self, multiplexer, dlci: int, max_frame_size: int, initial_tx_credits: int
+    ):
         super().__init__()
         self.multiplexer = multiplexer
         self.dlci = dlci
@@ -368,23 +397,23 @@
         )
 
     @staticmethod
-    def state_name(state):
+    def state_name(state: int) -> str:
         return DLC.STATE_NAMES[state]
 
-    def change_state(self, new_state):
+    def change_state(self, new_state: int) -> None:
         logger.debug(
             f'{self} state change -> {color(self.state_name(new_state), "magenta")}'
         )
         self.state = new_state
 
-    def send_frame(self, frame):
+    def send_frame(self, frame: RFCOMM_Frame) -> None:
         self.multiplexer.send_frame(frame)
 
-    def on_frame(self, frame):
+    def on_frame(self, frame: RFCOMM_Frame) -> None:
         handler = getattr(self, f'on_{frame.type_name()}_frame'.lower())
         handler(frame)
 
-    def on_sabm_frame(self, _frame):
+    def on_sabm_frame(self, _frame) -> None:
         if self.state != DLC.CONNECTING:
             logger.warning(
                 color('!!! received SABM when not in CONNECTING state', 'red')
@@ -404,7 +433,7 @@
         self.change_state(DLC.CONNECTED)
         self.emit('open')
 
-    def on_ua_frame(self, _frame):
+    def on_ua_frame(self, _frame) -> None:
         if self.state != DLC.CONNECTING:
             logger.warning(
                 color('!!! received SABM when not in CONNECTING state', 'red')
@@ -422,15 +451,15 @@
         self.change_state(DLC.CONNECTED)
         self.multiplexer.on_dlc_open_complete(self)
 
-    def on_dm_frame(self, frame):
+    def on_dm_frame(self, frame) -> None:
         # TODO: handle all states
         pass
 
-    def on_disc_frame(self, _frame):
+    def on_disc_frame(self, _frame) -> None:
         # TODO: handle all states
         self.send_frame(RFCOMM_Frame.ua(c_r=1 - self.c_r, dlci=self.dlci))
 
-    def on_uih_frame(self, frame):
+    def on_uih_frame(self, frame: RFCOMM_Frame) -> None:
         data = frame.information
         if frame.p_f == 1:
             # With credits
@@ -460,10 +489,10 @@
         # Check if there's anything to send (including credits)
         self.process_tx()
 
-    def on_ui_frame(self, frame):
+    def on_ui_frame(self, frame) -> None:
         pass
 
-    def on_mcc_msc(self, c_r, msc):
+    def on_mcc_msc(self, c_r, msc) -> None:
         if c_r:
             # Command
             logger.debug(f'<<< MCC MSC Command: {msc}')
@@ -477,7 +506,7 @@
             # Response
             logger.debug(f'<<< MCC MSC Response: {msc}')
 
-    def connect(self):
+    def connect(self) -> None:
         if self.state != DLC.INIT:
             raise InvalidStateError('invalid state')
 
@@ -485,7 +514,7 @@
         self.connection_result = asyncio.get_running_loop().create_future()
         self.send_frame(RFCOMM_Frame.sabm(c_r=self.c_r, dlci=self.dlci))
 
-    def accept(self):
+    def accept(self) -> None:
         if self.state != DLC.INIT:
             raise InvalidStateError('invalid state')
 
@@ -503,13 +532,13 @@
         self.send_frame(RFCOMM_Frame.uih(c_r=self.c_r, dlci=0, information=mcc))
         self.change_state(DLC.CONNECTING)
 
-    def rx_credits_needed(self):
+    def rx_credits_needed(self) -> int:
         if self.rx_credits <= self.rx_threshold:
             return RFCOMM_DEFAULT_INITIAL_RX_CREDITS - self.rx_credits
 
         return 0
 
-    def process_tx(self):
+    def process_tx(self) -> None:
         # Send anything we can (or an empty frame if we need to send rx credits)
         rx_credits_needed = self.rx_credits_needed()
         while (self.tx_buffer and self.tx_credits > 0) or rx_credits_needed > 0:
@@ -547,7 +576,7 @@
             rx_credits_needed = 0
 
     # Stream protocol
-    def write(self, data):
+    def write(self, data: Union[bytes, str]) -> None:
         # We can only send bytes
         if not isinstance(data, bytes):
             if isinstance(data, str):
@@ -559,7 +588,7 @@
         self.tx_buffer += data
         self.process_tx()
 
-    def drain(self):
+    def drain(self) -> None:
         # TODO
         pass
 
@@ -592,7 +621,13 @@
         RESET: 'RESET',
     }
 
-    def __init__(self, l2cap_channel, role):
+    connection_result: Optional[asyncio.Future]
+    disconnection_result: Optional[asyncio.Future]
+    open_result: Optional[asyncio.Future]
+    acceptor: Optional[Callable[[int], bool]]
+    dlcs: Dict[int, DLC]
+
+    def __init__(self, l2cap_channel: l2cap.Channel, role: int) -> None:
         super().__init__()
         self.role = role
         self.l2cap_channel = l2cap_channel
@@ -607,20 +642,20 @@
         l2cap_channel.sink = self.on_pdu
 
     @staticmethod
-    def state_name(state):
+    def state_name(state: int):
         return Multiplexer.STATE_NAMES[state]
 
-    def change_state(self, new_state):
+    def change_state(self, new_state: int) -> None:
         logger.debug(
             f'{self} state change -> {color(self.state_name(new_state), "cyan")}'
         )
         self.state = new_state
 
-    def send_frame(self, frame):
+    def send_frame(self, frame: RFCOMM_Frame) -> None:
         logger.debug(f'>>> Multiplexer sending {frame}')
         self.l2cap_channel.send_pdu(frame)
 
-    def on_pdu(self, pdu):
+    def on_pdu(self, pdu: bytes) -> None:
         frame = RFCOMM_Frame.from_bytes(pdu)
         logger.debug(f'<<< Multiplexer received {frame}')
 
@@ -640,18 +675,18 @@
                     return
                 dlc.on_frame(frame)
 
-    def on_frame(self, frame):
+    def on_frame(self, frame: RFCOMM_Frame) -> None:
         handler = getattr(self, f'on_{frame.type_name()}_frame'.lower())
         handler(frame)
 
-    def on_sabm_frame(self, _frame):
+    def on_sabm_frame(self, _frame) -> None:
         if self.state != Multiplexer.INIT:
             logger.debug('not in INIT state, ignoring SABM')
             return
         self.change_state(Multiplexer.CONNECTED)
         self.send_frame(RFCOMM_Frame.ua(c_r=1, dlci=0))
 
-    def on_ua_frame(self, _frame):
+    def on_ua_frame(self, _frame) -> None:
         if self.state == Multiplexer.CONNECTING:
             self.change_state(Multiplexer.CONNECTED)
             if self.connection_result:
@@ -663,7 +698,7 @@
                 self.disconnection_result.set_result(None)
                 self.disconnection_result = None
 
-    def on_dm_frame(self, _frame):
+    def on_dm_frame(self, _frame) -> None:
         if self.state == Multiplexer.OPENING:
             self.change_state(Multiplexer.CONNECTED)
             if self.open_result:
@@ -678,13 +713,13 @@
         else:
             logger.warning(f'unexpected state for DM: {self}')
 
-    def on_disc_frame(self, _frame):
+    def on_disc_frame(self, _frame) -> None:
         self.change_state(Multiplexer.DISCONNECTED)
         self.send_frame(
             RFCOMM_Frame.ua(c_r=0 if self.role == Multiplexer.INITIATOR else 1, dlci=0)
         )
 
-    def on_uih_frame(self, frame):
+    def on_uih_frame(self, frame: RFCOMM_Frame) -> None:
         (mcc_type, c_r, value) = RFCOMM_Frame.parse_mcc(frame.information)
 
         if mcc_type == RFCOMM_MCC_PN_TYPE:
@@ -694,10 +729,10 @@
             mcs = RFCOMM_MCC_MSC.from_bytes(value)
             self.on_mcc_msc(c_r, mcs)
 
-    def on_ui_frame(self, frame):
+    def on_ui_frame(self, frame) -> None:
         pass
 
-    def on_mcc_pn(self, c_r, pn):
+    def on_mcc_pn(self, c_r, pn) -> None:
         if c_r == 1:
             # Command
             logger.debug(f'<<< PN Command: {pn}')
@@ -736,14 +771,14 @@
             else:
                 logger.warning('ignoring PN response')
 
-    def on_mcc_msc(self, c_r, msc):
+    def on_mcc_msc(self, c_r, msc) -> None:
         dlc = self.dlcs.get(msc.dlci)
         if dlc is None:
             logger.warning(f'no dlc for DLCI {msc.dlci}')
             return
         dlc.on_mcc_msc(c_r, msc)
 
-    async def connect(self):
+    async def connect(self) -> None:
         if self.state != Multiplexer.INIT:
             raise InvalidStateError('invalid state')
 
@@ -752,7 +787,7 @@
         self.send_frame(RFCOMM_Frame.sabm(c_r=1, dlci=0))
         return await self.connection_result
 
-    async def disconnect(self):
+    async def disconnect(self) -> None:
         if self.state != Multiplexer.CONNECTED:
             return
 
@@ -765,7 +800,7 @@
         )
         await self.disconnection_result
 
-    async def open_dlc(self, channel):
+    async def open_dlc(self, channel: int) -> DLC:
         if self.state != Multiplexer.CONNECTED:
             if self.state == Multiplexer.OPENING:
                 raise InvalidStateError('open already in progress')
@@ -796,7 +831,7 @@
         self.open_result = None
         return result
 
-    def on_dlc_open_complete(self, dlc):
+    def on_dlc_open_complete(self, dlc: DLC):
         logger.debug(f'DLC [{dlc.dlci}] open complete')
         self.change_state(Multiplexer.CONNECTED)
         if self.open_result:
@@ -808,13 +843,16 @@
 
 # -----------------------------------------------------------------------------
 class Client:
-    def __init__(self, device, connection):
+    multiplexer: Optional[Multiplexer]
+    l2cap_channel: Optional[l2cap.Channel]
+
+    def __init__(self, device, connection) -> None:
         self.device = device
         self.connection = connection
         self.l2cap_channel = None
         self.multiplexer = None
 
-    async def start(self):
+    async def start(self) -> Multiplexer:
         # Create a new L2CAP connection
         try:
             self.l2cap_channel = await self.device.l2cap_channel_manager.connect(
@@ -824,6 +862,7 @@
             logger.warning(f'L2CAP connection failed: {error}')
             raise
 
+        assert self.l2cap_channel is not None
         # Create a mutliplexer to manage DLCs with the server
         self.multiplexer = Multiplexer(self.l2cap_channel, Multiplexer.INITIATOR)
 
@@ -832,7 +871,9 @@
 
         return self.multiplexer
 
-    async def shutdown(self):
+    async def shutdown(self) -> None:
+        if self.multiplexer is None:
+            return
         # Disconnect the multiplexer
         await self.multiplexer.disconnect()
         self.multiplexer = None
@@ -843,7 +884,9 @@
 
 # -----------------------------------------------------------------------------
 class Server(EventEmitter):
-    def __init__(self, device):
+    acceptors: Dict[int, Callable[[DLC], None]]
+
+    def __init__(self, device) -> None:
         super().__init__()
         self.device = device
         self.multiplexer = None
@@ -852,7 +895,7 @@
         # Register ourselves with the L2CAP channel manager
         device.register_l2cap_server(RFCOMM_PSM, self.on_connection)
 
-    def listen(self, acceptor, channel=0):
+    def listen(self, acceptor: Callable[[DLC], None], channel: int = 0) -> int:
         if channel:
             if channel in self.acceptors:
                 # Busy
@@ -874,11 +917,11 @@
         self.acceptors[channel] = acceptor
         return channel
 
-    def on_connection(self, l2cap_channel):
+    def on_connection(self, l2cap_channel: l2cap.Channel) -> None:
         logger.debug(f'+++ new L2CAP connection: {l2cap_channel}')
         l2cap_channel.on('open', lambda: self.on_l2cap_channel_open(l2cap_channel))
 
-    def on_l2cap_channel_open(self, l2cap_channel):
+    def on_l2cap_channel_open(self, l2cap_channel: l2cap.Channel) -> None:
         logger.debug(f'$$$ L2CAP channel open: {l2cap_channel}')
 
         # Create a new multiplexer for the channel
@@ -889,10 +932,10 @@
         # Notify
         self.emit('start', multiplexer)
 
-    def accept_dlc(self, channel_number):
+    def accept_dlc(self, channel_number: int) -> bool:
         return channel_number in self.acceptors
 
-    def on_dlc(self, dlc):
+    def on_dlc(self, dlc: DLC) -> None:
         logger.debug(f'@@@ new DLC connected: {dlc}')
 
         # Let the acceptor know
diff --git a/bumble/smp.py b/bumble/smp.py
index f3fbf27..c93ee9c 100644
--- a/bumble/smp.py
+++ b/bumble/smp.py
@@ -25,6 +25,7 @@
 from __future__ import annotations
 import logging
 import asyncio
+import enum
 import secrets
 from typing import (
     TYPE_CHECKING,
@@ -553,20 +554,16 @@
 
 
 # -----------------------------------------------------------------------------
-class Session:
-    # Pairing methods
+class PairingMethod(enum.IntEnum):
     JUST_WORKS = 0
     NUMERIC_COMPARISON = 1
     PASSKEY = 2
     OOB = 3
+    CTKD_OVER_CLASSIC = 4
 
-    PAIRING_METHOD_NAMES = {
-        JUST_WORKS: 'JUST_WORKS',
-        NUMERIC_COMPARISON: 'NUMERIC_COMPARISON',
-        PASSKEY: 'PASSKEY',
-        OOB: 'OOB',
-    }
 
+# -----------------------------------------------------------------------------
+class Session:
     # I/O Capability to pairing method decision matrix
     #
     # See Bluetooth spec @ Vol 3, part H - Table 2.8: Mapping of IO Capabilities to Key
@@ -581,47 +578,50 @@
     # (False).
     PAIRING_METHODS = {
         SMP_DISPLAY_ONLY_IO_CAPABILITY: {
-            SMP_DISPLAY_ONLY_IO_CAPABILITY: JUST_WORKS,
-            SMP_DISPLAY_YES_NO_IO_CAPABILITY: JUST_WORKS,
-            SMP_KEYBOARD_ONLY_IO_CAPABILITY: (PASSKEY, True, False),
-            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: JUST_WORKS,
-            SMP_KEYBOARD_DISPLAY_IO_CAPABILITY: (PASSKEY, True, False),
+            SMP_DISPLAY_ONLY_IO_CAPABILITY: PairingMethod.JUST_WORKS,
+            SMP_DISPLAY_YES_NO_IO_CAPABILITY: PairingMethod.JUST_WORKS,
+            SMP_KEYBOARD_ONLY_IO_CAPABILITY: (PairingMethod.PASSKEY, True, False),
+            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: PairingMethod.JUST_WORKS,
+            SMP_KEYBOARD_DISPLAY_IO_CAPABILITY: (PairingMethod.PASSKEY, True, False),
         },
         SMP_DISPLAY_YES_NO_IO_CAPABILITY: {
-            SMP_DISPLAY_ONLY_IO_CAPABILITY: JUST_WORKS,
-            SMP_DISPLAY_YES_NO_IO_CAPABILITY: (JUST_WORKS, NUMERIC_COMPARISON),
-            SMP_KEYBOARD_ONLY_IO_CAPABILITY: (PASSKEY, True, False),
-            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: JUST_WORKS,
+            SMP_DISPLAY_ONLY_IO_CAPABILITY: PairingMethod.JUST_WORKS,
+            SMP_DISPLAY_YES_NO_IO_CAPABILITY: (
+                PairingMethod.JUST_WORKS,
+                PairingMethod.NUMERIC_COMPARISON,
+            ),
+            SMP_KEYBOARD_ONLY_IO_CAPABILITY: (PairingMethod.PASSKEY, True, False),
+            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: PairingMethod.JUST_WORKS,
             SMP_KEYBOARD_DISPLAY_IO_CAPABILITY: (
-                (PASSKEY, True, False),
-                NUMERIC_COMPARISON,
+                (PairingMethod.PASSKEY, True, False),
+                PairingMethod.NUMERIC_COMPARISON,
             ),
         },
         SMP_KEYBOARD_ONLY_IO_CAPABILITY: {
-            SMP_DISPLAY_ONLY_IO_CAPABILITY: (PASSKEY, False, True),
-            SMP_DISPLAY_YES_NO_IO_CAPABILITY: (PASSKEY, False, True),
-            SMP_KEYBOARD_ONLY_IO_CAPABILITY: (PASSKEY, False, False),
-            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: JUST_WORKS,
-            SMP_KEYBOARD_DISPLAY_IO_CAPABILITY: (PASSKEY, False, True),
+            SMP_DISPLAY_ONLY_IO_CAPABILITY: (PairingMethod.PASSKEY, False, True),
+            SMP_DISPLAY_YES_NO_IO_CAPABILITY: (PairingMethod.PASSKEY, False, True),
+            SMP_KEYBOARD_ONLY_IO_CAPABILITY: (PairingMethod.PASSKEY, False, False),
+            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: PairingMethod.JUST_WORKS,
+            SMP_KEYBOARD_DISPLAY_IO_CAPABILITY: (PairingMethod.PASSKEY, False, True),
         },
         SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: {
-            SMP_DISPLAY_ONLY_IO_CAPABILITY: JUST_WORKS,
-            SMP_DISPLAY_YES_NO_IO_CAPABILITY: JUST_WORKS,
-            SMP_KEYBOARD_ONLY_IO_CAPABILITY: JUST_WORKS,
-            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: JUST_WORKS,
-            SMP_KEYBOARD_DISPLAY_IO_CAPABILITY: JUST_WORKS,
+            SMP_DISPLAY_ONLY_IO_CAPABILITY: PairingMethod.JUST_WORKS,
+            SMP_DISPLAY_YES_NO_IO_CAPABILITY: PairingMethod.JUST_WORKS,
+            SMP_KEYBOARD_ONLY_IO_CAPABILITY: PairingMethod.JUST_WORKS,
+            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: PairingMethod.JUST_WORKS,
+            SMP_KEYBOARD_DISPLAY_IO_CAPABILITY: PairingMethod.JUST_WORKS,
         },
         SMP_KEYBOARD_DISPLAY_IO_CAPABILITY: {
-            SMP_DISPLAY_ONLY_IO_CAPABILITY: (PASSKEY, False, True),
+            SMP_DISPLAY_ONLY_IO_CAPABILITY: (PairingMethod.PASSKEY, False, True),
             SMP_DISPLAY_YES_NO_IO_CAPABILITY: (
-                (PASSKEY, False, True),
-                NUMERIC_COMPARISON,
+                (PairingMethod.PASSKEY, False, True),
+                PairingMethod.NUMERIC_COMPARISON,
             ),
-            SMP_KEYBOARD_ONLY_IO_CAPABILITY: (PASSKEY, True, False),
-            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: JUST_WORKS,
+            SMP_KEYBOARD_ONLY_IO_CAPABILITY: (PairingMethod.PASSKEY, True, False),
+            SMP_NO_INPUT_NO_OUTPUT_IO_CAPABILITY: PairingMethod.JUST_WORKS,
             SMP_KEYBOARD_DISPLAY_IO_CAPABILITY: (
-                (PASSKEY, True, False),
-                NUMERIC_COMPARISON,
+                (PairingMethod.PASSKEY, True, False),
+                PairingMethod.NUMERIC_COMPARISON,
             ),
         },
     }
@@ -664,7 +664,7 @@
         self.passkey_ready = asyncio.Event()
         self.passkey_step = 0
         self.passkey_display = False
-        self.pairing_method = 0
+        self.pairing_method: PairingMethod = PairingMethod.JUST_WORKS
         self.pairing_config = pairing_config
         self.wait_before_continuing: Optional[asyncio.Future[None]] = None
         self.completed = False
@@ -769,19 +769,23 @@
     def decide_pairing_method(
         self, auth_req: int, initiator_io_capability: int, responder_io_capability: int
     ) -> None:
+        if self.connection.transport == BT_BR_EDR_TRANSPORT:
+            self.pairing_method = PairingMethod.CTKD_OVER_CLASSIC
+            return
         if (not self.mitm) and (auth_req & SMP_MITM_AUTHREQ == 0):
-            self.pairing_method = self.JUST_WORKS
+            self.pairing_method = PairingMethod.JUST_WORKS
             return
 
         details = self.PAIRING_METHODS[initiator_io_capability][responder_io_capability]  # type: ignore[index]
         if isinstance(details, tuple) and len(details) == 2:
             # One entry for legacy pairing and one for secure connections
             details = details[1 if self.sc else 0]
-        if isinstance(details, int):
+        if isinstance(details, PairingMethod):
             # Just a method ID
             self.pairing_method = details
         else:
             # PASSKEY method, with a method ID and display/input flags
+            assert isinstance(details[0], PairingMethod)
             self.pairing_method = details[0]
             self.passkey_display = details[1 if self.is_initiator else 2]
 
@@ -858,10 +862,13 @@
             self.tk = self.passkey.to_bytes(16, byteorder='little')
             logger.debug(f'TK from passkey = {self.tk.hex()}')
 
-        self.connection.abort_on(
-            'disconnection',
-            self.pairing_config.delegate.display_number(self.passkey, digits=6),
-        )
+        try:
+            self.connection.abort_on(
+                'disconnection',
+                self.pairing_config.delegate.display_number(self.passkey, digits=6),
+            )
+        except Exception as error:
+            logger.warning(f'exception while displaying number: {error}')
 
     def input_passkey(self, next_steps: Optional[Callable[[], None]] = None) -> None:
         # Prompt the user for the passkey displayed on the peer
@@ -929,9 +936,12 @@
         if self.sc:
 
             async def next_steps() -> None:
-                if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
+                if self.pairing_method in (
+                    PairingMethod.JUST_WORKS,
+                    PairingMethod.NUMERIC_COMPARISON,
+                ):
                     z = 0
-                elif self.pairing_method == self.PASSKEY:
+                elif self.pairing_method == PairingMethod.PASSKEY:
                     # We need a passkey
                     await self.passkey_ready.wait()
                     assert self.passkey
@@ -983,6 +993,19 @@
             )
         )
 
+    def send_identity_address_command(self) -> None:
+        identity_address = {
+            None: self.connection.self_address,
+            Address.PUBLIC_DEVICE_ADDRESS: self.manager.device.public_address,
+            Address.RANDOM_DEVICE_ADDRESS: self.manager.device.random_address,
+        }[self.pairing_config.identity_address_type]
+        self.send_command(
+            SMP_Identity_Address_Information_Command(
+                addr_type=identity_address.address_type,
+                bd_addr=identity_address,
+            )
+        )
+
     def start_encryption(self, key: bytes) -> None:
         # We can now encrypt the connection with the short term key, so that we can
         # distribute the long term and/or other keys over an encrypted connection
@@ -1006,6 +1029,7 @@
         self.ltk = crypto.h6(ilk, b'brle')
 
     def distribute_keys(self) -> None:
+
         # Distribute the keys as required
         if self.is_initiator:
             # CTKD: Derive LTK from LinkKey
@@ -1035,12 +1059,7 @@
                         identity_resolving_key=self.manager.device.irk
                     )
                 )
-                self.send_command(
-                    SMP_Identity_Address_Information_Command(
-                        addr_type=self.connection.self_address.address_type,
-                        bd_addr=self.connection.self_address,
-                    )
-                )
+                self.send_identity_address_command()
 
             # Distribute CSRK
             csrk = bytes(16)  # FIXME: testing
@@ -1084,12 +1103,7 @@
                         identity_resolving_key=self.manager.device.irk
                     )
                 )
-                self.send_command(
-                    SMP_Identity_Address_Information_Command(
-                        addr_type=self.connection.self_address.address_type,
-                        bd_addr=self.connection.self_address,
-                    )
-                )
+                self.send_identity_address_command()
 
             # Distribute CSRK
             csrk = bytes(16)  # FIXME: testing
@@ -1224,7 +1238,7 @@
         # Create an object to hold the keys
         keys = PairingKeys()
         keys.address_type = peer_address.address_type
-        authenticated = self.pairing_method != self.JUST_WORKS
+        authenticated = self.pairing_method != PairingMethod.JUST_WORKS
         if self.sc or self.connection.transport == BT_BR_EDR_TRANSPORT:
             keys.ltk = PairingKeys.Key(value=self.ltk, authenticated=authenticated)
         else:
@@ -1300,7 +1314,11 @@
         self, command: SMP_Pairing_Request_Command
     ) -> None:
         # Check if the request should proceed
-        accepted = await self.pairing_config.delegate.accept()
+        try:
+            accepted = await self.pairing_config.delegate.accept()
+        except Exception as error:
+            logger.warning(f'exception while accepting: {error}')
+            accepted = False
         if not accepted:
             logger.debug('pairing rejected by delegate')
             self.send_pairing_failed(SMP_PAIRING_NOT_SUPPORTED_ERROR)
@@ -1323,9 +1341,7 @@
         self.decide_pairing_method(
             command.auth_req, command.io_capability, self.io_capability
         )
-        logger.debug(
-            f'pairing method: {self.PAIRING_METHOD_NAMES[self.pairing_method]}'
-        )
+        logger.debug(f'pairing method: {self.pairing_method.name}')
 
         # Key distribution
         (
@@ -1341,7 +1357,7 @@
 
         # Display a passkey if we need to
         if not self.sc:
-            if self.pairing_method == self.PASSKEY and self.passkey_display:
+            if self.pairing_method == PairingMethod.PASSKEY and self.passkey_display:
                 self.display_passkey()
 
         # Respond
@@ -1382,9 +1398,7 @@
         self.decide_pairing_method(
             command.auth_req, self.io_capability, command.io_capability
         )
-        logger.debug(
-            f'pairing method: {self.PAIRING_METHOD_NAMES[self.pairing_method]}'
-        )
+        logger.debug(f'pairing method: {self.pairing_method.name}')
 
         # Key distribution
         if (
@@ -1400,13 +1414,16 @@
         self.compute_peer_expected_distributions(self.responder_key_distribution)
 
         # Start phase 2
-        if self.sc:
-            if self.pairing_method == self.PASSKEY:
+        if self.pairing_method == PairingMethod.CTKD_OVER_CLASSIC:
+            # Authentication is already done in SMP, so remote shall start keys distribution immediately
+            return
+        elif self.sc:
+            if self.pairing_method == PairingMethod.PASSKEY:
                 self.display_or_input_passkey()
 
             self.send_public_key_command()
         else:
-            if self.pairing_method == self.PASSKEY:
+            if self.pairing_method == PairingMethod.PASSKEY:
                 self.display_or_input_passkey(self.send_pairing_confirm_command)
             else:
                 self.send_pairing_confirm_command()
@@ -1418,7 +1435,10 @@
             self.send_pairing_random_command()
         else:
             # If the method is PASSKEY, now is the time to input the code
-            if self.pairing_method == self.PASSKEY and not self.passkey_display:
+            if (
+                self.pairing_method == PairingMethod.PASSKEY
+                and not self.passkey_display
+            ):
                 self.input_passkey(self.send_pairing_confirm_command)
             else:
                 self.send_pairing_confirm_command()
@@ -1426,11 +1446,14 @@
     def on_smp_pairing_confirm_command_secure_connections(
         self, _: SMP_Pairing_Confirm_Command
     ) -> None:
-        if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
+        if self.pairing_method in (
+            PairingMethod.JUST_WORKS,
+            PairingMethod.NUMERIC_COMPARISON,
+        ):
             if self.is_initiator:
                 self.r = crypto.r()
                 self.send_pairing_random_command()
-        elif self.pairing_method == self.PASSKEY:
+        elif self.pairing_method == PairingMethod.PASSKEY:
             if self.is_initiator:
                 self.send_pairing_random_command()
             else:
@@ -1486,13 +1509,16 @@
     def on_smp_pairing_random_command_secure_connections(
         self, command: SMP_Pairing_Random_Command
     ) -> None:
-        if self.pairing_method == self.PASSKEY and self.passkey is None:
+        if self.pairing_method == PairingMethod.PASSKEY and self.passkey is None:
             logger.warning('no passkey entered, ignoring command')
             return
 
         # pylint: disable=too-many-return-statements
         if self.is_initiator:
-            if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
+            if self.pairing_method in (
+                PairingMethod.JUST_WORKS,
+                PairingMethod.NUMERIC_COMPARISON,
+            ):
                 assert self.confirm_value
                 # Check that the random value matches what was committed to earlier
                 confirm_verifier = crypto.f4(
@@ -1502,7 +1528,7 @@
                     self.confirm_value, confirm_verifier, SMP_CONFIRM_VALUE_FAILED_ERROR
                 ):
                     return
-            elif self.pairing_method == self.PASSKEY:
+            elif self.pairing_method == PairingMethod.PASSKEY:
                 assert self.passkey and self.confirm_value
                 # Check that the random value matches what was committed to earlier
                 confirm_verifier = crypto.f4(
@@ -1525,9 +1551,12 @@
             else:
                 return
         else:
-            if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
+            if self.pairing_method in (
+                PairingMethod.JUST_WORKS,
+                PairingMethod.NUMERIC_COMPARISON,
+            ):
                 self.send_pairing_random_command()
-            elif self.pairing_method == self.PASSKEY:
+            elif self.pairing_method == PairingMethod.PASSKEY:
                 assert self.passkey and self.confirm_value
                 # Check that the random value matches what was committed to earlier
                 confirm_verifier = crypto.f4(
@@ -1558,10 +1587,13 @@
         (mac_key, self.ltk) = crypto.f5(self.dh_key, self.na, self.nb, a, b)
 
         # Compute the DH Key checks
-        if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
+        if self.pairing_method in (
+            PairingMethod.JUST_WORKS,
+            PairingMethod.NUMERIC_COMPARISON,
+        ):
             ra = bytes(16)
             rb = ra
-        elif self.pairing_method == self.PASSKEY:
+        elif self.pairing_method == PairingMethod.PASSKEY:
             assert self.passkey
             ra = self.passkey.to_bytes(16, byteorder='little')
             rb = ra
@@ -1585,13 +1617,16 @@
                     self.wait_before_continuing.set_result(None)
 
         # Prompt the user for confirmation if needed
-        if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
+        if self.pairing_method in (
+            PairingMethod.JUST_WORKS,
+            PairingMethod.NUMERIC_COMPARISON,
+        ):
             # Compute the 6-digit code
             code = crypto.g2(self.pka, self.pkb, self.na, self.nb) % 1000000
 
             # Ask for user confirmation
             self.wait_before_continuing = asyncio.get_running_loop().create_future()
-            if self.pairing_method == self.JUST_WORKS:
+            if self.pairing_method == PairingMethod.JUST_WORKS:
                 self.prompt_user_for_confirmation(next_steps)
             else:
                 self.prompt_user_for_numeric_comparison(code, next_steps)
@@ -1628,13 +1663,16 @@
         if self.is_initiator:
             self.send_pairing_confirm_command()
         else:
-            if self.pairing_method == self.PASSKEY:
+            if self.pairing_method == PairingMethod.PASSKEY:
                 self.display_or_input_passkey()
 
             # Send our public key back to the initiator
             self.send_public_key_command()
 
-            if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
+            if self.pairing_method in (
+                PairingMethod.JUST_WORKS,
+                PairingMethod.NUMERIC_COMPARISON,
+            ):
                 # We can now send the confirmation value
                 self.send_pairing_confirm_command()
 
@@ -1805,7 +1843,7 @@
             self.device.abort_on('flush', store_keys())
 
         # Notify the device
-        self.device.on_pairing(session.connection, keys, session.sc)
+        self.device.on_pairing(session.connection, identity_address, keys, session.sc)
 
     def on_pairing_failure(self, session: Session, reason: int) -> None:
         self.device.on_pairing_failure(session.connection, reason)
diff --git a/bumble/transport/usb.py b/bumble/transport/usb.py
index 68c5a6f..13cad60 100644
--- a/bumble/transport/usb.py
+++ b/bumble/transport/usb.py
@@ -206,10 +206,11 @@
                     logger.debug('OUT transfer likely already completed')
 
     class UsbPacketSource(asyncio.Protocol, ParserSource):
-        def __init__(self, context, device, acl_in, events_in):
+        def __init__(self, context, device, metadata, acl_in, events_in):
             super().__init__()
             self.context = context
             self.device = device
+            self.metadata = metadata
             self.acl_in = acl_in
             self.events_in = events_in
             self.loop = asyncio.get_running_loop()
@@ -510,6 +511,10 @@
             f'events_in=0x{events_in:02X}, '
         )
 
+        device_metadata = {
+            'vendor_id': found.getVendorID(),
+            'product_id': found.getProductID(),
+        }
         device = found.open()
 
         # Auto-detach the kernel driver if supported
@@ -535,7 +540,7 @@
             except usb1.USBError:
                 logger.warning('failed to set configuration')
 
-        source = UsbPacketSource(context, device, acl_in, events_in)
+        source = UsbPacketSource(context, device, device_metadata, acl_in, events_in)
         sink = UsbPacketSink(device, acl_out)
         return UsbTransport(context, device, interface, setting, source, sink)
     except usb1.USBError as error:
diff --git a/docs/mkdocs/mkdocs.yml b/docs/mkdocs/mkdocs.yml
index 0ddc982..0cf65f1 100644
--- a/docs/mkdocs/mkdocs.yml
+++ b/docs/mkdocs/mkdocs.yml
@@ -36,6 +36,9 @@
     - HCI Socket: transports/hci_socket.md
     - Android Emulator: transports/android_emulator.md
     - File: transports/file.md
+  - Drivers:
+    - Overview: drivers/index.md
+    - Realtek: drivers/realtek.md
   - API:
     - Guide: api/guide.md
     - Examples: api/examples.md
@@ -44,6 +47,7 @@
     - Overview: apps_and_tools/index.md
     - Console: apps_and_tools/console.md
     - Bench: apps_and_tools/bench.md
+    - Speaker: apps_and_tools/speaker.md
     - HCI Bridge: apps_and_tools/hci_bridge.md
     - Golden Gate Bridge: apps_and_tools/gg_bridge.md
     - Show: apps_and_tools/show.md
diff --git a/docs/mkdocs/src/apps_and_tools/index.md b/docs/mkdocs/src/apps_and_tools/index.md
index fe7af56..0c2b4d5 100644
--- a/docs/mkdocs/src/apps_and_tools/index.md
+++ b/docs/mkdocs/src/apps_and_tools/index.md
@@ -11,4 +11,5 @@
   * [HCI Bridge](hci_bridge.md) - a HCI transport bridge to connect two HCI transports and filter/snoop the HCI packets
   * [Golden Gate Bridge](gg_bridge.md) - a bridge between GATT and UDP to use with the Golden Gate "stack tool"
   * [Show](show.md) - Parse a file with HCI packets and print the details of each packet in a human readable form
+  * [Speaker](speaker.md) - Virtual Bluetooth speaker, with a command line and browser-based UI.
   * [Link Relay](link_relay.md) - WebSocket relay for virtual RemoteLink instances to communicate with each other.
diff --git a/docs/mkdocs/src/apps_and_tools/speaker.md b/docs/mkdocs/src/apps_and_tools/speaker.md
new file mode 100644
index 0000000..5569b9d
--- /dev/null
+++ b/docs/mkdocs/src/apps_and_tools/speaker.md
@@ -0,0 +1,86 @@
+SPEAKER APP
+===========
+
+![logo](../images/speaker_screenshot.png){ width=400 height=320 }
+
+The Speaker app is virtual Bluetooth speaker (A2DP sink).
+The app runs as a command-line executable, but also offers an optional simple
+web-browser-based user interface.
+
+# General Usage
+You can invoke the app either as `bumble-speaker` when installed as command
+from `pip`, or `python3 apps/speaker/speaker.py` when running from a source
+distribution.
+
+```
+Usage: speaker.py [OPTIONS] TRANSPORT
+
+  Run the speaker.
+
+Options:
+  --codec [sbc|aac]          [default: aac]
+  --discover                 Discover remote endpoints once connected
+  --output NAME              Send audio to this named output (may be used more
+                             than once for multiple outputs)
+  --ui-port HTTP_PORT        HTTP port for the UI server  [default: 7654]
+  --connect ADDRESS_OR_NAME  Address or name to connect to
+  --device-config FILENAME   Device configuration file
+  --help                     Show this message and exit.
+```
+
+# Connection
+By default, the virtual speaker will wait for another device (like a phone or
+computer) to connect to it (and possibly pair). Alternatively, the speaker can
+be told to initiate a connection to a remote device, using the `--connect` 
+option.
+
+# Outputs
+The speaker can have one or more outputs. By default, the only output is a text
+display on the console, as well as a browser-based user interface if connected.
+In addition, a file output can be used, in which case the received audio data is
+saved to a specified file.
+Finally, if the host computer on which your are running the application has `ffplay`
+as an available command line executable, the `@ffplay` output can be selected, in 
+which case the received audio will be played on the computer's builtin speakers via
+a pipe to `ffplay`. (see the [ffplay documentation](https://www.ffmpeg.org/ffplay.html)
+for details)
+
+# Web User Interface
+When the speaker app starts, it prints out on the console the local URL at which you
+may point a browser (Chrome recommended for full functionality). The console line
+specifying the local UI URL will look like:
+```
+UI HTTP server at http://127.0.0.1:7654
+```
+
+By default, the web UI will show the status of the connection, as well as a realtime
+graph of the received audio bandwidth.
+In order to also hear the received audio, you need to click the `Audio on` button
+(this is due to the fact that most browsers will require some user interface with the
+page before granting access to the audio output APIs).
+
+# Examples
+
+In the following examples, we use a single USB Bluetooth controllers `usb:0`. Other 
+transports can be used of course.
+
+!!! example "Start the speaker and wait for a connection"
+    ```
+    $ bumble-speaker usb:0
+    ```
+
+!!! example "Start the speaker and save the AAC audio to a file named `audio.aac`."
+    ```
+    $ bumble-speaker --output audio.aac usb:0
+    ```
+
+!!! example "Start the speaker and save the SBC audio to a file named `audio.sbc`."
+    ```
+    $ bumble-speaker --codec sbc --output audio.sbc usb:0
+    ```
+
+!!! example "Start the speaker and connect it to a phone at address `B8:7B:C5:05:57:ED`."
+    ```
+    $ bumble-speaker --connect B8:7B:C5:05:57:ED usb:0
+    ```
+
diff --git a/docs/mkdocs/src/drivers/index.md b/docs/mkdocs/src/drivers/index.md
new file mode 100644
index 0000000..a904e00
--- /dev/null
+++ b/docs/mkdocs/src/drivers/index.md
@@ -0,0 +1,10 @@
+DRIVERS
+=======
+
+Some Bluetooth controllers require a driver to function properly.
+This may include, for instance, loading a Firmware image or patch,
+loading a configuration.
+
+Drivers included in the module are:
+
+  * [Realtek](realtek.md): Loading of Firmware and Config for Realtek USB dongles.
\ No newline at end of file
diff --git a/docs/mkdocs/src/drivers/realtek.md b/docs/mkdocs/src/drivers/realtek.md
new file mode 100644
index 0000000..acbce49
--- /dev/null
+++ b/docs/mkdocs/src/drivers/realtek.md
@@ -0,0 +1,62 @@
+REALTEK DRIVER
+==============
+
+This driver supports loading firmware images and optional config data to 
+USB dongles with a Realtek chipset.
+A number of USB dongles are supported, but likely not all.
+When using a USB dongle, the USB product ID and manufacturer ID are used
+to find whether a matching set of firmware image and config data
+is needed for that specific model. If a match exists, the driver will try
+load the firmware image and, if needed, config data.
+The driver will look for those files by name, in order, in:
+
+  * The directory specified by the environment variable `BUMBLE_RTK_FIRMWARE_DIR`
+    if set.
+  * The directory `<package-dir>/drivers/rtk_fw` where `<package-dir>` is the directory
+    where the `bumble` package is installed.
+  * The current directory.
+
+
+Obtaining Firmware Images and Config Data
+-----------------------------------------
+
+Firmware images and config data may be obtained from a variety of online
+sources.
+To facilitate finding a downloading the, the utility program `bumble-rtk-fw-download`
+may be used.
+
+```
+Usage: bumble-rtk-fw-download [OPTIONS]
+
+  Download RTK firmware images and configs.
+
+Options:
+  --output-dir TEXT               Output directory where the files will be
+                                  saved  [default: .]
+  --source [linux-kernel|realtek-opensource|linux-from-scratch]
+                                  [default: linux-kernel]
+  --single TEXT                   Only download a single image set, by its
+                                  base name
+  --force                         Overwrite files if they already exist
+  --parse                         Parse the FW image after saving
+  --help                          Show this message and exit.
+```
+
+Utility
+-------
+
+The `bumble-rtk-util` utility may be used to interact with a Realtek USB dongle
+and/or firmware images.
+
+```
+Usage: bumble-rtk-util [OPTIONS] COMMAND [ARGS]...
+
+Options:
+  --help  Show this message and exit.
+
+Commands:
+  drop   Drop a firmware image from the USB dongle.
+  info   Get the firmware info from a USB dongle.
+  load   Load a firmware image into the USB dongle.
+  parse  Parse a firmware image.
+```
\ No newline at end of file
diff --git a/docs/mkdocs/src/images/speaker_screenshot.png b/docs/mkdocs/src/images/speaker_screenshot.png
new file mode 100644
index 0000000..fd34880
--- /dev/null
+++ b/docs/mkdocs/src/images/speaker_screenshot.png
Binary files differ
diff --git a/docs/mkdocs/src/transports/ws_client.md b/docs/mkdocs/src/transports/ws_client.md
index ad9c245..6d9cacb 100644
--- a/docs/mkdocs/src/transports/ws_client.md
+++ b/docs/mkdocs/src/transports/ws_client.md
@@ -1,11 +1,11 @@
-UDP TRANSPORT
-=============
+WEBSOCKET CLIENT TRANSPORT
+==========================
 
-The UDP transport is a UDP socket, receiving packets on a specified port number, and sending packets to a specified host and port number.
+The WebSocket Client transport is WebSocket connection to a WebSocket server over which HCI packets
+are sent and received.
 
 ## Moniker
-The moniker syntax for a UDP transport is: `udp:<local-host>:<local-port>,<remote-host>:<remote-port>`.
+The moniker syntax for a WebSocket Client transport is: `ws-client:<ws-url>`
 
 !!! example
-    `udp:0.0.0.0:9000,127.0.0.1:9001`
-    UDP transport where packets are received on port `9000` and sent to `127.0.0.1` on port `9001`
+    `ws-client:ws://localhost:1234/some/path`
diff --git a/docs/mkdocs/src/transports/ws_server.md b/docs/mkdocs/src/transports/ws_server.md
index ad9c245..8986d3f 100644
--- a/docs/mkdocs/src/transports/ws_server.md
+++ b/docs/mkdocs/src/transports/ws_server.md
@@ -1,11 +1,13 @@
-UDP TRANSPORT
-=============
+WEBSOCKET SERVER TRANSPORT
+==========================
 
-The UDP transport is a UDP socket, receiving packets on a specified port number, and sending packets to a specified host and port number.
+The WebSocket Server transport is WebSocket server that accepts connections from a WebSocket
+client. HCI packets are sent and received over the connection.
 
 ## Moniker
-The moniker syntax for a UDP transport is: `udp:<local-host>:<local-port>,<remote-host>:<remote-port>`.
+The moniker syntax for a WebSocket Server transport is: `ws-server:<host>:<port>`,
+where `<host>` may be the address of a local network interface, or `_`to accept connections on all local network interfaces. `<port>` is the TCP port number on which to accept connections.
+
 
 !!! example
-    `udp:0.0.0.0:9000,127.0.0.1:9001`
-    UDP transport where packets are received on port `9000` and sent to `127.0.0.1` on port `9001`
+    `ws-server:_:9001`
diff --git a/examples/run_classic_connect.py b/examples/run_classic_connect.py
index bb46bf7..3ae6ed8 100644
--- a/examples/run_classic_connect.py
+++ b/examples/run_classic_connect.py
@@ -23,7 +23,7 @@
 
 from bumble.device import Device
 from bumble.transport import open_transport_or_link
-from bumble.core import BT_BR_EDR_TRANSPORT, BT_L2CAP_PROTOCOL_ID
+from bumble.core import BT_BR_EDR_TRANSPORT, BT_L2CAP_PROTOCOL_ID, CommandTimeoutError
 from bumble.sdp import (
     Client as SDP_Client,
     SDP_PUBLIC_BROWSE_ROOT,
@@ -48,62 +48,70 @@
         # Create a device
         device = Device.from_config_file_with_hci(sys.argv[1], hci_source, hci_sink)
         device.classic_enabled = True
+        device.le_enabled = False
         await device.power_on()
 
-    async def connect(target_address):
-        print(f'=== Connecting to {target_address}...')
-        connection = await device.connect(target_address, transport=BT_BR_EDR_TRANSPORT)
-        print(f'=== Connected to {connection.peer_address}!')
-
-        # Connect to the SDP Server
-        sdp_client = SDP_Client(device)
-        await sdp_client.connect(connection)
-
-        # List all services in the root browse group
-        service_record_handles = await sdp_client.search_services(
-            [SDP_PUBLIC_BROWSE_ROOT]
-        )
-        print(color('\n==================================', 'blue'))
-        print(color('SERVICES:', 'yellow'), service_record_handles)
-
-        # For each service in the root browse group, get all its attributes
-        for service_record_handle in service_record_handles:
-            attributes = await sdp_client.get_attributes(
-                service_record_handle, [SDP_ALL_ATTRIBUTES_RANGE]
-            )
-            print(color(f'SERVICE {service_record_handle:04X} attributes:', 'yellow'))
-            for attribute in attributes:
-                print('  ', attribute.to_string(with_colors=True))
-
-        # Search for services with an L2CAP service attribute
-        search_result = await sdp_client.search_attributes(
-            [BT_L2CAP_PROTOCOL_ID], [SDP_ALL_ATTRIBUTES_RANGE]
-        )
-        print(color('\n==================================', 'blue'))
-        print(color('SEARCH RESULTS:', 'yellow'))
-        for attribute_list in search_result:
-            print(color('SERVICE:', 'green'))
-            print(
-                '  '
-                + '\n  '.join(
-                    [
-                        attribute.to_string(with_colors=True)
-                        for attribute in attribute_list
-                    ]
+        async def connect(target_address):
+            print(f'=== Connecting to {target_address}...')
+            try:
+                connection = await device.connect(
+                    target_address, transport=BT_BR_EDR_TRANSPORT
                 )
+            except CommandTimeoutError:
+                print('!!! Connection timed out')
+                return
+            print(f'=== Connected to {connection.peer_address}!')
+
+            # Connect to the SDP Server
+            sdp_client = SDP_Client(device)
+            await sdp_client.connect(connection)
+
+            # List all services in the root browse group
+            service_record_handles = await sdp_client.search_services(
+                [SDP_PUBLIC_BROWSE_ROOT]
             )
+            print(color('\n==================================', 'blue'))
+            print(color('SERVICES:', 'yellow'), service_record_handles)
 
-        await sdp_client.disconnect()
-        await hci_source.wait_for_termination()
+            # For each service in the root browse group, get all its attributes
+            for service_record_handle in service_record_handles:
+                attributes = await sdp_client.get_attributes(
+                    service_record_handle, [SDP_ALL_ATTRIBUTES_RANGE]
+                )
+                print(
+                    color(f'SERVICE {service_record_handle:04X} attributes:', 'yellow')
+                )
+                for attribute in attributes:
+                    print('  ', attribute.to_string(with_colors=True))
 
-    # Connect to a peer
-    target_addresses = sys.argv[3:]
-    await asyncio.wait(
-        [
-            asyncio.create_task(connect(target_address))
-            for target_address in target_addresses
-        ]
-    )
+            # Search for services with an L2CAP service attribute
+            search_result = await sdp_client.search_attributes(
+                [BT_L2CAP_PROTOCOL_ID], [SDP_ALL_ATTRIBUTES_RANGE]
+            )
+            print(color('\n==================================', 'blue'))
+            print(color('SEARCH RESULTS:', 'yellow'))
+            for attribute_list in search_result:
+                print(color('SERVICE:', 'green'))
+                print(
+                    '  '
+                    + '\n  '.join(
+                        [
+                            attribute.to_string(with_colors=True)
+                            for attribute in attribute_list
+                        ]
+                    )
+                )
+
+            await sdp_client.disconnect()
+
+        # Connect to a peer
+        target_addresses = sys.argv[3:]
+        await asyncio.wait(
+            [
+                asyncio.create_task(connect(target_address))
+                for target_address in target_addresses
+            ]
+        )
 
 
 # -----------------------------------------------------------------------------
diff --git a/examples/run_scanner.py b/examples/run_scanner.py
index bdd7fba..4a094b9 100644
--- a/examples/run_scanner.py
+++ b/examples/run_scanner.py
@@ -62,7 +62,7 @@
             print(
                 f'>>> {color(advertisement.address, address_color)} '
                 f'[{color(address_type_string, type_color)}]'
-                f'{address_qualifier}:{separator}RSSI:{advertisement.rssi}'
+                f'{address_qualifier}:{separator}RSSI: {advertisement.rssi}'
                 f'{separator}'
                 f'{advertisement.data.to_string(separator)}'
             )
diff --git a/examples/speaker.json b/examples/speaker.json
new file mode 100644
index 0000000..61ce80d
--- /dev/null
+++ b/examples/speaker.json
@@ -0,0 +1,5 @@
+{
+    "name": "Bumble Speaker",
+    "class_of_device": 2360324,
+    "keystore": "JsonKeyStore"
+}
diff --git a/rust/.gitignore b/rust/.gitignore
new file mode 100644
index 0000000..40d9aca
--- /dev/null
+++ b/rust/.gitignore
@@ -0,0 +1,2 @@
+/target
+/.idea
\ No newline at end of file
diff --git a/rust/Cargo.lock b/rust/Cargo.lock
new file mode 100644
index 0000000..1492cfb
--- /dev/null
+++ b/rust/Cargo.lock
@@ -0,0 +1,1235 @@
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+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
+ "windows_x86_64_msvc",
+]
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diff --git a/rust/Cargo.toml b/rust/Cargo.toml
new file mode 100644
index 0000000..8b7c723
--- /dev/null
+++ b/rust/Cargo.toml
@@ -0,0 +1,49 @@
+[package]
+name = "bumble"
+description = "Rust API for the Bumble Bluetooth stack"
+version = "0.1.0"
+edition = "2021"
+license = "Apache-2.0"
+homepage = "https://google.github.io/bumble/index.html"
+repository = "https://github.com/google/bumble"
+documentation = "https://docs.rs/crate/bumble"
+authors = ["Marshall Pierce <marshallpierce@google.com>"]
+keywords = ["bluetooth", "ble"]
+categories = ["api-bindings", "network-programming"]
+rust-version = "1.69.0"
+
+[dependencies]
+pyo3 = { version = "0.18.3", features = ["macros"] }
+pyo3-asyncio = { version = "0.18.0", features = ["tokio-runtime"] }
+tokio = { version = "1.28.2" }
+nom = "7.1.3"
+strum = "0.25.0"
+strum_macros = "0.25.0"
+hex = "0.4.3"
+itertools = "0.11.0"
+lazy_static = "1.4.0"
+thiserror = "1.0.41"
+
+[dev-dependencies]
+tokio = { version = "1.28.2", features = ["full"] }
+tempfile = "3.6.0"
+nix = "0.26.2"
+anyhow = "1.0.71"
+pyo3 = { version = "0.18.3", features = ["macros", "anyhow"] }
+pyo3-asyncio = { version = "0.18.0", features = ["tokio-runtime", "attributes", "testing"] }
+clap = { version = "4.3.3", features = ["derive"] }
+owo-colors = "3.5.0"
+log = "0.4.19"
+env_logger = "0.10.0"
+rusb = "0.9.2"
+rand = "0.8.5"
+
+# test entry point that uses pyo3_asyncio's test harness
+[[test]]
+name = "pytests"
+path = "pytests/pytests.rs"
+harness = false
+
+[features]
+anyhow = ["pyo3/anyhow"]
+pyo3-asyncio-attributes = ["pyo3-asyncio/attributes"]
\ No newline at end of file
diff --git a/rust/README.md b/rust/README.md
new file mode 100644
index 0000000..fd591c7
--- /dev/null
+++ b/rust/README.md
@@ -0,0 +1,42 @@
+# What is this?
+
+Rust wrappers around the [Bumble](https://github.com/google/bumble) Python API.
+
+Method calls are mapped to the equivalent Python, and return types adapted where
+relevant.
+
+See the `examples` directory for usage.
+
+# Usage
+
+Set up a virtualenv for Bumble, or otherwise have an isolated Python environment
+for Bumble and its dependencies.
+
+Due to Python being
+[picky about how its sys path is set up](https://github.com/PyO3/pyo3/issues/1741,
+it's necessary to explicitly point to the virtualenv's `site-packages`. Use
+suitable virtualenv paths as appropriate for your OS, as seen here running
+the `battery_client` example:
+
+```
+PYTHONPATH=..:~/.virtualenvs/bumble/lib/python3.10/site-packages/ \
+    cargo run --example battery_client -- \
+    --transport android-netsim --target-addr F0:F1:F2:F3:F4:F5
+```
+
+Run the corresponding `battery_server` Python example, and launch an emulator in
+Android Studio (currently, Canary is required) to run netsim.
+
+# Development
+
+Run the tests:
+
+```
+PYTHONPATH=.. cargo test
+```
+
+Check lints:
+
+```
+cargo clippy --all-targets
+```
\ No newline at end of file
diff --git a/rust/examples/battery_client.rs b/rust/examples/battery_client.rs
new file mode 100644
index 0000000..007ccb6
--- /dev/null
+++ b/rust/examples/battery_client.rs
@@ -0,0 +1,112 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Counterpart to the Python example `battery_server.py`.
+//!
+//! Start an Android emulator from Android Studio, or otherwise have netsim running.
+//!
+//! Run the server from the project root:
+//! ```
+//! PYTHONPATH=. python examples/battery_server.py \
+//!     examples/device1.json android-netsim
+//! ```
+//!
+//! Then run this example from the `rust` directory:
+//!
+//! ```
+//! PYTHONPATH=..:/path/to/virtualenv/site-packages/ \
+//!     cargo run --example battery_client -- \
+//!     --transport android-netsim \
+//!     --target-addr F0:F1:F2:F3:F4:F5
+//! ```
+
+use bumble::wrapper::{
+    device::{Device, Peer},
+    profile::BatteryServiceProxy,
+    transport::Transport,
+    PyObjectExt,
+};
+use clap::Parser as _;
+use log::info;
+use owo_colors::OwoColorize;
+use pyo3::prelude::*;
+
+#[pyo3_asyncio::tokio::main]
+async fn main() -> PyResult<()> {
+    env_logger::builder()
+        .filter_level(log::LevelFilter::Info)
+        .init();
+
+    let cli = Cli::parse();
+
+    let transport = Transport::open(cli.transport).await?;
+
+    let device = Device::with_hci(
+        "Bumble",
+        "F0:F1:F2:F3:F4:F5",
+        transport.source()?,
+        transport.sink()?,
+    )?;
+
+    device.power_on().await?;
+
+    let conn = device.connect(&cli.target_addr).await?;
+    let mut peer = Peer::new(conn)?;
+    for mut s in peer.discover_services().await? {
+        s.discover_characteristics().await?;
+    }
+    let battery_service = peer
+        .create_service_proxy::<BatteryServiceProxy>()?
+        .ok_or(anyhow::anyhow!("No battery service found"))?;
+
+    let mut battery_level_char = battery_service
+        .battery_level()?
+        .ok_or(anyhow::anyhow!("No battery level characteristic"))?;
+    info!(
+        "{} {}",
+        "Initial Battery Level:".green(),
+        battery_level_char
+            .read_value()
+            .await?
+            .extract_with_gil::<u32>()?
+    );
+    battery_level_char
+        .subscribe(|_py, args| {
+            info!(
+                "{} {:?}",
+                "Battery level update:".green(),
+                args.get_item(0)?.extract::<u32>()?,
+            );
+            Ok(())
+        })
+        .await?;
+
+    // wait until user kills the process
+    tokio::signal::ctrl_c().await?;
+    Ok(())
+}
+
+#[derive(clap::Parser)]
+#[command(author, version, about, long_about = None)]
+struct Cli {
+    /// Bumble transport spec.
+    ///
+    /// <https://google.github.io/bumble/transports/index.html>
+    #[arg(long)]
+    transport: String,
+
+    /// Address to connect to
+    #[arg(long)]
+    target_addr: String,
+}
diff --git a/rust/examples/broadcast.rs b/rust/examples/broadcast.rs
new file mode 100644
index 0000000..f87b644
--- /dev/null
+++ b/rust/examples/broadcast.rs
@@ -0,0 +1,98 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use anyhow::anyhow;
+use bumble::{
+    adv::{AdvertisementDataBuilder, CommonDataType},
+    wrapper::{
+        device::Device,
+        logging::{bumble_env_logging_level, py_logging_basic_config},
+        transport::Transport,
+    },
+};
+use clap::Parser as _;
+use pyo3::PyResult;
+use rand::Rng;
+use std::path;
+
+#[pyo3_asyncio::tokio::main]
+async fn main() -> PyResult<()> {
+    env_logger::builder()
+        .filter_level(log::LevelFilter::Info)
+        .init();
+
+    let cli = Cli::parse();
+
+    if cli.log_hci {
+        py_logging_basic_config(bumble_env_logging_level("DEBUG"))?;
+    }
+
+    let transport = Transport::open(cli.transport).await?;
+
+    let mut device = Device::from_config_file_with_hci(
+        &cli.device_config,
+        transport.source()?,
+        transport.sink()?,
+    )?;
+
+    let mut adv_data = AdvertisementDataBuilder::new();
+
+    adv_data
+        .append(
+            CommonDataType::CompleteLocalName,
+            "Bumble from Rust".as_bytes(),
+        )
+        .map_err(|e| anyhow!(e))?;
+
+    // Randomized TX power
+    adv_data
+        .append(
+            CommonDataType::TxPowerLevel,
+            &[rand::thread_rng().gen_range(-100_i8..=20) as u8],
+        )
+        .map_err(|e| anyhow!(e))?;
+
+    device.set_advertising_data(adv_data)?;
+    device.power_on().await?;
+
+    println!("Advertising...");
+    device.start_advertising(true).await?;
+
+    // wait until user kills the process
+    tokio::signal::ctrl_c().await?;
+
+    println!("Stopping...");
+    device.stop_advertising().await?;
+
+    Ok(())
+}
+
+#[derive(clap::Parser)]
+#[command(author, version, about, long_about = None)]
+struct Cli {
+    /// Bumble device config.
+    ///
+    /// See, for instance, `examples/device1.json` in the Python project.
+    #[arg(long)]
+    device_config: path::PathBuf,
+    /// Bumble transport spec.
+    ///
+    /// <https://google.github.io/bumble/transports/index.html>
+    #[arg(long)]
+    transport: String,
+
+    /// Log HCI commands
+    #[arg(long)]
+    log_hci: bool,
+}
diff --git a/rust/examples/scanner.rs b/rust/examples/scanner.rs
new file mode 100644
index 0000000..1b68ea5
--- /dev/null
+++ b/rust/examples/scanner.rs
@@ -0,0 +1,185 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Counterpart to the Python example `run_scanner.py`.
+//!
+//! Device deduplication is done here rather than relying on the controller's filtering to provide
+//! for additional features, like the ability to make deduplication time-bounded.
+
+use bumble::{
+    adv::CommonDataType,
+    wrapper::{
+        core::AdvertisementDataUnit, device::Device, hci::AddressType, transport::Transport,
+    },
+};
+use clap::Parser as _;
+use itertools::Itertools;
+use owo_colors::{OwoColorize, Style};
+use pyo3::PyResult;
+use std::{
+    collections,
+    sync::{Arc, Mutex},
+    time,
+};
+
+#[pyo3_asyncio::tokio::main]
+async fn main() -> PyResult<()> {
+    env_logger::builder()
+        .filter_level(log::LevelFilter::Info)
+        .init();
+
+    let cli = Cli::parse();
+
+    let transport = Transport::open(cli.transport).await?;
+
+    let mut device = Device::with_hci(
+        "Bumble",
+        "F0:F1:F2:F3:F4:F5",
+        transport.source()?,
+        transport.sink()?,
+    )?;
+
+    // in practice, devices can send multiple advertisements from the same address, so we keep
+    // track of a timestamp for each set of data
+    let seen_advertisements = Arc::new(Mutex::new(collections::HashMap::<
+        Vec<u8>,
+        collections::HashMap<Vec<AdvertisementDataUnit>, time::Instant>,
+    >::new()));
+
+    let seen_adv_clone = seen_advertisements.clone();
+    device.on_advertisement(move |_py, adv| {
+        let rssi = adv.rssi()?;
+        let data_units = adv.data()?.data_units()?;
+        let addr = adv.address()?;
+
+        let show_adv = if cli.filter_duplicates {
+            let addr_bytes = addr.as_le_bytes()?;
+
+            let mut seen_adv_cache = seen_adv_clone.lock().unwrap();
+            let expiry_duration = time::Duration::from_secs(cli.dedup_expiry_secs);
+
+            let advs_from_addr = seen_adv_cache
+                .entry(addr_bytes)
+                .or_insert_with(collections::HashMap::new);
+            // we expect cache hits to be the norm, so we do a separate lookup to avoid cloning
+            // on every lookup with entry()
+            let show = if let Some(prev) = advs_from_addr.get_mut(&data_units) {
+                let expired = prev.elapsed() > expiry_duration;
+                *prev = time::Instant::now();
+                expired
+            } else {
+                advs_from_addr.insert(data_units.clone(), time::Instant::now());
+                true
+            };
+
+            // clean out anything we haven't seen in a while
+            advs_from_addr.retain(|_, instant| instant.elapsed() <= expiry_duration);
+
+            show
+        } else {
+            true
+        };
+
+        if !show_adv {
+            return Ok(());
+        }
+
+        let addr_style = if adv.is_connectable()? {
+            Style::new().yellow()
+        } else {
+            Style::new().red()
+        };
+
+        let (type_style, qualifier) = match adv.address()?.address_type()? {
+            AddressType::PublicIdentity | AddressType::PublicDevice => (Style::new().cyan(), ""),
+            _ => {
+                if addr.is_static()? {
+                    (Style::new().green(), "(static)")
+                } else if addr.is_resolvable()? {
+                    (Style::new().magenta(), "(resolvable)")
+                } else {
+                    (Style::new().default_color(), "")
+                }
+            }
+        };
+
+        println!(
+            ">>> {} [{:?}] {qualifier}:\n  RSSI: {}",
+            addr.as_hex()?.style(addr_style),
+            addr.address_type()?.style(type_style),
+            rssi,
+        );
+
+        data_units.into_iter().for_each(|(code, data)| {
+            let matching = CommonDataType::for_type_code(code).collect::<Vec<_>>();
+            let code_str = if matching.is_empty() {
+                format!("0x{}", hex::encode_upper([code.into()]))
+            } else {
+                matching
+                    .iter()
+                    .map(|t| format!("{}", t))
+                    .join(" / ")
+                    .blue()
+                    .to_string()
+            };
+
+            // use the first matching type's formatted data, if any
+            let data_str = matching
+                .iter()
+                .filter_map(|t| {
+                    t.format_data(&data).map(|formatted| {
+                        format!(
+                            "{} {}",
+                            formatted,
+                            format!("(raw: 0x{})", hex::encode_upper(&data)).dimmed()
+                        )
+                    })
+                })
+                .next()
+                .unwrap_or_else(|| format!("0x{}", hex::encode_upper(&data)));
+
+            println!("  [{}]: {}", code_str, data_str)
+        });
+
+        Ok(())
+    })?;
+
+    device.power_on().await?;
+    // do our own dedup
+    device.start_scanning(false).await?;
+
+    // wait until user kills the process
+    tokio::signal::ctrl_c().await?;
+
+    Ok(())
+}
+
+#[derive(clap::Parser)]
+#[command(author, version, about, long_about = None)]
+struct Cli {
+    /// Bumble transport spec.
+    ///
+    /// <https://google.github.io/bumble/transports/index.html>
+    #[arg(long)]
+    transport: String,
+
+    /// Filter duplicate advertisements
+    #[arg(long, default_value_t = false)]
+    filter_duplicates: bool,
+
+    /// How long before a deduplicated advertisement that hasn't been seen in a while is considered
+    /// fresh again, in seconds
+    #[arg(long, default_value_t = 10, requires = "filter_duplicates")]
+    dedup_expiry_secs: u64,
+}
diff --git a/rust/examples/usb_probe.rs b/rust/examples/usb_probe.rs
new file mode 100644
index 0000000..3ba3b61
--- /dev/null
+++ b/rust/examples/usb_probe.rs
@@ -0,0 +1,342 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Rust version of the Python `usb_probe.py`.
+//!
+//! This tool lists all the USB devices, with details about each device.
+//! For each device, the different possible Bumble transport strings that can
+//! refer to it are listed. If the device is known to be a Bluetooth HCI device,
+//! its identifier is printed in reverse colors, and the transport names in cyan color.
+//! For other devices, regardless of their type, the transport names are printed
+//! in red. Whether that device is actually a Bluetooth device or not depends on
+//! whether it is a Bluetooth device that uses a non-standard Class, or some other
+//! type of device (there's no way to tell).
+
+use clap::Parser as _;
+use itertools::Itertools as _;
+use owo_colors::{OwoColorize, Style};
+use rusb::{Device, DeviceDescriptor, Direction, TransferType, UsbContext};
+use std::{
+    collections::{HashMap, HashSet},
+    time::Duration,
+};
+
+const USB_DEVICE_CLASS_DEVICE: u8 = 0x00;
+const USB_DEVICE_CLASS_WIRELESS_CONTROLLER: u8 = 0xE0;
+const USB_DEVICE_SUBCLASS_RF_CONTROLLER: u8 = 0x01;
+const USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER: u8 = 0x01;
+
+fn main() -> anyhow::Result<()> {
+    let cli = Cli::parse();
+
+    let mut bt_dev_count = 0;
+    let mut device_serials_by_id: HashMap<(u16, u16), HashSet<String>> = HashMap::new();
+    for device in rusb::devices()?.iter() {
+        let device_desc = device.device_descriptor().unwrap();
+
+        let class_info = ClassInfo::from(&device_desc);
+        let handle = device.open()?;
+        let timeout = Duration::from_secs(1);
+        // some devices don't have languages
+        let lang = handle
+            .read_languages(timeout)
+            .ok()
+            .and_then(|langs| langs.into_iter().next());
+        let serial = lang.and_then(|l| {
+            handle
+                .read_serial_number_string(l, &device_desc, timeout)
+                .ok()
+        });
+        let mfg = lang.and_then(|l| {
+            handle
+                .read_manufacturer_string(l, &device_desc, timeout)
+                .ok()
+        });
+        let product = lang.and_then(|l| handle.read_product_string(l, &device_desc, timeout).ok());
+
+        let is_hci = is_bluetooth_hci(&device, &device_desc)?;
+        let addr_style = if is_hci {
+            bt_dev_count += 1;
+            Style::new().black().on_yellow()
+        } else {
+            Style::new().yellow().on_black()
+        };
+
+        let mut transport_names = Vec::new();
+        let basic_transport_name = format!(
+            "usb:{:04X}:{:04X}",
+            device_desc.vendor_id(),
+            device_desc.product_id()
+        );
+
+        if is_hci {
+            transport_names.push(format!("usb:{}", bt_dev_count - 1));
+        }
+
+        let device_id = (device_desc.vendor_id(), device_desc.product_id());
+        if !device_serials_by_id.contains_key(&device_id) {
+            transport_names.push(basic_transport_name.clone());
+        } else {
+            transport_names.push(format!(
+                "{}#{}",
+                basic_transport_name,
+                device_serials_by_id
+                    .get(&device_id)
+                    .map(|serials| serials.len())
+                    .unwrap_or(0)
+            ))
+        }
+
+        if let Some(s) = &serial {
+            if !device_serials_by_id
+                .get(&device_id)
+                .map(|serials| serials.contains(s))
+                .unwrap_or(false)
+            {
+                transport_names.push(format!("{}/{}", basic_transport_name, s))
+            }
+        }
+
+        println!(
+            "{}",
+            format!(
+                "ID {:04X}:{:04X}",
+                device_desc.vendor_id(),
+                device_desc.product_id()
+            )
+            .style(addr_style)
+        );
+        if !transport_names.is_empty() {
+            let style = if is_hci {
+                Style::new().cyan()
+            } else {
+                Style::new().red()
+            };
+            println!(
+                "{:26}{}",
+                "  Bumble Transport Names:".blue(),
+                transport_names.iter().map(|n| n.style(style)).join(" or ")
+            )
+        }
+        println!(
+            "{:26}{:03}/{:03}",
+            "  Bus/Device:".green(),
+            device.bus_number(),
+            device.address()
+        );
+        println!(
+            "{:26}{}",
+            "  Class:".green(),
+            class_info.formatted_class_name()
+        );
+        println!(
+            "{:26}{}",
+            "  Subclass/Protocol:".green(),
+            class_info.formatted_subclass_protocol()
+        );
+        if let Some(s) = serial {
+            println!("{:26}{}", "  Serial:".green(), s);
+            device_serials_by_id
+                .entry(device_id)
+                .or_insert(HashSet::new())
+                .insert(s);
+        }
+        if let Some(m) = mfg {
+            println!("{:26}{}", "  Manufacturer:".green(), m);
+        }
+        if let Some(p) = product {
+            println!("{:26}{}", "  Product:".green(), p);
+        }
+
+        if cli.verbose {
+            print_device_details(&device, &device_desc)?;
+        }
+
+        println!();
+    }
+
+    Ok(())
+}
+
+fn is_bluetooth_hci<T: UsbContext>(
+    device: &Device<T>,
+    device_desc: &DeviceDescriptor,
+) -> rusb::Result<bool> {
+    if device_desc.class_code() == USB_DEVICE_CLASS_WIRELESS_CONTROLLER
+        && device_desc.sub_class_code() == USB_DEVICE_SUBCLASS_RF_CONTROLLER
+        && device_desc.protocol_code() == USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER
+    {
+        Ok(true)
+    } else if device_desc.class_code() == USB_DEVICE_CLASS_DEVICE {
+        for i in 0..device_desc.num_configurations() {
+            for interface in device.config_descriptor(i)?.interfaces() {
+                for d in interface.descriptors() {
+                    if d.class_code() == USB_DEVICE_CLASS_WIRELESS_CONTROLLER
+                        && d.sub_class_code() == USB_DEVICE_SUBCLASS_RF_CONTROLLER
+                        && d.protocol_code() == USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER
+                    {
+                        return Ok(true);
+                    }
+                }
+            }
+        }
+
+        Ok(false)
+    } else {
+        Ok(false)
+    }
+}
+
+fn print_device_details<T: UsbContext>(
+    device: &Device<T>,
+    device_desc: &DeviceDescriptor,
+) -> anyhow::Result<()> {
+    for i in 0..device_desc.num_configurations() {
+        println!("  Configuration {}", i + 1);
+        for interface in device.config_descriptor(i)?.interfaces() {
+            let interface_descriptors: Vec<_> = interface.descriptors().collect();
+            for d in &interface_descriptors {
+                let class_info =
+                    ClassInfo::new(d.class_code(), d.sub_class_code(), d.protocol_code());
+
+                println!(
+                    "      Interface: {}{} ({}, {})",
+                    interface.number(),
+                    if interface_descriptors.len() > 1 {
+                        format!("/{}", d.setting_number())
+                    } else {
+                        String::new()
+                    },
+                    class_info.formatted_class_name(),
+                    class_info.formatted_subclass_protocol()
+                );
+
+                for e in d.endpoint_descriptors() {
+                    println!(
+                        "        Endpoint {:#04X}: {} {}",
+                        e.address(),
+                        match e.transfer_type() {
+                            TransferType::Control => "CONTROL",
+                            TransferType::Isochronous => "ISOCHRONOUS",
+                            TransferType::Bulk => "BULK",
+                            TransferType::Interrupt => "INTERRUPT",
+                        },
+                        match e.direction() {
+                            Direction::In => "IN",
+                            Direction::Out => "OUT",
+                        }
+                    )
+                }
+            }
+        }
+    }
+
+    Ok(())
+}
+
+struct ClassInfo {
+    class: u8,
+    sub_class: u8,
+    protocol: u8,
+}
+
+impl ClassInfo {
+    fn new(class: u8, sub_class: u8, protocol: u8) -> Self {
+        Self {
+            class,
+            sub_class,
+            protocol,
+        }
+    }
+
+    fn class_name(&self) -> Option<&str> {
+        match self.class {
+            0x00 => Some("Device"),
+            0x01 => Some("Audio"),
+            0x02 => Some("Communications and CDC Control"),
+            0x03 => Some("Human Interface Device"),
+            0x05 => Some("Physical"),
+            0x06 => Some("Still Imaging"),
+            0x07 => Some("Printer"),
+            0x08 => Some("Mass Storage"),
+            0x09 => Some("Hub"),
+            0x0A => Some("CDC Data"),
+            0x0B => Some("Smart Card"),
+            0x0D => Some("Content Security"),
+            0x0E => Some("Video"),
+            0x0F => Some("Personal Healthcare"),
+            0x10 => Some("Audio/Video"),
+            0x11 => Some("Billboard"),
+            0x12 => Some("USB Type-C Bridge"),
+            0x3C => Some("I3C"),
+            0xDC => Some("Diagnostic"),
+            USB_DEVICE_CLASS_WIRELESS_CONTROLLER => Some("Wireless Controller"),
+            0xEF => Some("Miscellaneous"),
+            0xFE => Some("Application Specific"),
+            0xFF => Some("Vendor Specific"),
+            _ => None,
+        }
+    }
+
+    fn protocol_name(&self) -> Option<&str> {
+        match self.class {
+            USB_DEVICE_CLASS_WIRELESS_CONTROLLER => match self.sub_class {
+                0x01 => match self.protocol {
+                    0x01 => Some("Bluetooth"),
+                    0x02 => Some("UWB"),
+                    0x03 => Some("Remote NDIS"),
+                    0x04 => Some("Bluetooth AMP"),
+                    _ => None,
+                },
+                _ => None,
+            },
+            _ => None,
+        }
+    }
+
+    fn formatted_class_name(&self) -> String {
+        self.class_name()
+            .map(|s| s.to_string())
+            .unwrap_or_else(|| format!("{:#04X}", self.class))
+    }
+
+    fn formatted_subclass_protocol(&self) -> String {
+        format!(
+            "{}/{}{}",
+            self.sub_class,
+            self.protocol,
+            self.protocol_name()
+                .map(|s| format!(" [{}]", s))
+                .unwrap_or_else(String::new)
+        )
+    }
+}
+
+impl From<&DeviceDescriptor> for ClassInfo {
+    fn from(value: &DeviceDescriptor) -> Self {
+        Self::new(
+            value.class_code(),
+            value.sub_class_code(),
+            value.protocol_code(),
+        )
+    }
+}
+
+#[derive(clap::Parser)]
+#[command(author, version, about, long_about = None)]
+struct Cli {
+    /// Show additional info for each USB device
+    #[arg(long, default_value_t = false)]
+    verbose: bool,
+}
diff --git a/rust/pytests/pytests.rs b/rust/pytests/pytests.rs
new file mode 100644
index 0000000..da331f3
--- /dev/null
+++ b/rust/pytests/pytests.rs
@@ -0,0 +1,20 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#[pyo3_asyncio::tokio::main]
+async fn main() -> pyo3::PyResult<()> {
+    pyo3_asyncio::testing::main().await
+}
+
+mod wrapper;
diff --git a/rust/pytests/wrapper.rs b/rust/pytests/wrapper.rs
new file mode 100644
index 0000000..1c1f9d0
--- /dev/null
+++ b/rust/pytests/wrapper.rs
@@ -0,0 +1,37 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use bumble::{wrapper, wrapper::transport::Transport};
+use nix::sys::stat::Mode;
+use pyo3::prelude::*;
+
+#[pyo3_asyncio::tokio::test]
+async fn fifo_transport_can_open() -> PyResult<()> {
+    let dir = tempfile::tempdir().unwrap();
+    let mut fifo = dir.path().to_path_buf();
+    fifo.push("bumble-transport-fifo");
+    nix::unistd::mkfifo(&fifo, Mode::S_IRWXU).unwrap();
+
+    let mut t = Transport::open(format!("file:{}", fifo.to_str().unwrap())).await?;
+
+    t.close().await?;
+
+    Ok(())
+}
+
+#[pyo3_asyncio::tokio::test]
+async fn company_ids() -> PyResult<()> {
+    assert!(wrapper::assigned_numbers::COMPANY_IDS.len() > 2000);
+    Ok(())
+}
diff --git a/rust/src/adv.rs b/rust/src/adv.rs
new file mode 100644
index 0000000..8a4c979
--- /dev/null
+++ b/rust/src/adv.rs
@@ -0,0 +1,446 @@
+//! BLE advertisements.
+
+use crate::wrapper::assigned_numbers::{COMPANY_IDS, SERVICE_IDS};
+use crate::wrapper::core::{Uuid128, Uuid16, Uuid32};
+use itertools::Itertools;
+use nom::{combinator, multi, number};
+use std::fmt;
+use strum::IntoEnumIterator;
+
+/// The numeric code for a common data type.
+///
+/// For known types, see [CommonDataType], or use this type directly for non-assigned codes.
+#[derive(PartialEq, Eq, Debug, Clone, Copy, Hash)]
+pub struct CommonDataTypeCode(u8);
+
+impl From<CommonDataType> for CommonDataTypeCode {
+    fn from(value: CommonDataType) -> Self {
+        let byte = match value {
+            CommonDataType::Flags => 0x01,
+            CommonDataType::IncompleteListOf16BitServiceClassUuids => 0x02,
+            CommonDataType::CompleteListOf16BitServiceClassUuids => 0x03,
+            CommonDataType::IncompleteListOf32BitServiceClassUuids => 0x04,
+            CommonDataType::CompleteListOf32BitServiceClassUuids => 0x05,
+            CommonDataType::IncompleteListOf128BitServiceClassUuids => 0x06,
+            CommonDataType::CompleteListOf128BitServiceClassUuids => 0x07,
+            CommonDataType::ShortenedLocalName => 0x08,
+            CommonDataType::CompleteLocalName => 0x09,
+            CommonDataType::TxPowerLevel => 0x0A,
+            CommonDataType::ClassOfDevice => 0x0D,
+            CommonDataType::SimplePairingHashC192 => 0x0E,
+            CommonDataType::SimplePairingRandomizerR192 => 0x0F,
+            // These two both really have type code 0x10! D:
+            CommonDataType::DeviceId => 0x10,
+            CommonDataType::SecurityManagerTkValue => 0x10,
+            CommonDataType::SecurityManagerOutOfBandFlags => 0x11,
+            CommonDataType::PeripheralConnectionIntervalRange => 0x12,
+            CommonDataType::ListOf16BitServiceSolicitationUuids => 0x14,
+            CommonDataType::ListOf128BitServiceSolicitationUuids => 0x15,
+            CommonDataType::ServiceData16BitUuid => 0x16,
+            CommonDataType::PublicTargetAddress => 0x17,
+            CommonDataType::RandomTargetAddress => 0x18,
+            CommonDataType::Appearance => 0x19,
+            CommonDataType::AdvertisingInterval => 0x1A,
+            CommonDataType::LeBluetoothDeviceAddress => 0x1B,
+            CommonDataType::LeRole => 0x1C,
+            CommonDataType::SimplePairingHashC256 => 0x1D,
+            CommonDataType::SimplePairingRandomizerR256 => 0x1E,
+            CommonDataType::ListOf32BitServiceSolicitationUuids => 0x1F,
+            CommonDataType::ServiceData32BitUuid => 0x20,
+            CommonDataType::ServiceData128BitUuid => 0x21,
+            CommonDataType::LeSecureConnectionsConfirmationValue => 0x22,
+            CommonDataType::LeSecureConnectionsRandomValue => 0x23,
+            CommonDataType::Uri => 0x24,
+            CommonDataType::IndoorPositioning => 0x25,
+            CommonDataType::TransportDiscoveryData => 0x26,
+            CommonDataType::LeSupportedFeatures => 0x27,
+            CommonDataType::ChannelMapUpdateIndication => 0x28,
+            CommonDataType::PbAdv => 0x29,
+            CommonDataType::MeshMessage => 0x2A,
+            CommonDataType::MeshBeacon => 0x2B,
+            CommonDataType::BigInfo => 0x2C,
+            CommonDataType::BroadcastCode => 0x2D,
+            CommonDataType::ResolvableSetIdentifier => 0x2E,
+            CommonDataType::AdvertisingIntervalLong => 0x2F,
+            CommonDataType::ThreeDInformationData => 0x3D,
+            CommonDataType::ManufacturerSpecificData => 0xFF,
+        };
+
+        Self(byte)
+    }
+}
+
+impl From<u8> for CommonDataTypeCode {
+    fn from(value: u8) -> Self {
+        Self(value)
+    }
+}
+
+impl From<CommonDataTypeCode> for u8 {
+    fn from(value: CommonDataTypeCode) -> Self {
+        value.0
+    }
+}
+
+/// Data types for assigned type codes.
+///
+/// See Bluetooth Assigned Numbers § 2.3
+#[derive(Debug, Clone, Copy, PartialEq, Eq, strum_macros::EnumIter)]
+#[allow(missing_docs)]
+pub enum CommonDataType {
+    Flags,
+    IncompleteListOf16BitServiceClassUuids,
+    CompleteListOf16BitServiceClassUuids,
+    IncompleteListOf32BitServiceClassUuids,
+    CompleteListOf32BitServiceClassUuids,
+    IncompleteListOf128BitServiceClassUuids,
+    CompleteListOf128BitServiceClassUuids,
+    ShortenedLocalName,
+    CompleteLocalName,
+    TxPowerLevel,
+    ClassOfDevice,
+    SimplePairingHashC192,
+    SimplePairingRandomizerR192,
+    DeviceId,
+    SecurityManagerTkValue,
+    SecurityManagerOutOfBandFlags,
+    PeripheralConnectionIntervalRange,
+    ListOf16BitServiceSolicitationUuids,
+    ListOf128BitServiceSolicitationUuids,
+    ServiceData16BitUuid,
+    PublicTargetAddress,
+    RandomTargetAddress,
+    Appearance,
+    AdvertisingInterval,
+    LeBluetoothDeviceAddress,
+    LeRole,
+    SimplePairingHashC256,
+    SimplePairingRandomizerR256,
+    ListOf32BitServiceSolicitationUuids,
+    ServiceData32BitUuid,
+    ServiceData128BitUuid,
+    LeSecureConnectionsConfirmationValue,
+    LeSecureConnectionsRandomValue,
+    Uri,
+    IndoorPositioning,
+    TransportDiscoveryData,
+    LeSupportedFeatures,
+    ChannelMapUpdateIndication,
+    PbAdv,
+    MeshMessage,
+    MeshBeacon,
+    BigInfo,
+    BroadcastCode,
+    ResolvableSetIdentifier,
+    AdvertisingIntervalLong,
+    ThreeDInformationData,
+    ManufacturerSpecificData,
+}
+
+impl CommonDataType {
+    /// Iterate over the zero, one, or more matching types for the provided code.
+    ///
+    /// `0x10` maps to both Device Id and Security Manager TK Value, so multiple matching types
+    /// may exist for a single code.
+    pub fn for_type_code(code: CommonDataTypeCode) -> impl Iterator<Item = CommonDataType> {
+        Self::iter().filter(move |t| CommonDataTypeCode::from(*t) == code)
+    }
+
+    /// Apply type-specific human-oriented formatting to data, if any is applicable
+    pub fn format_data(&self, data: &[u8]) -> Option<String> {
+        match self {
+            Self::Flags => Some(Flags::matching(data).map(|f| format!("{:?}", f)).join(",")),
+            Self::CompleteListOf16BitServiceClassUuids
+            | Self::IncompleteListOf16BitServiceClassUuids
+            | Self::ListOf16BitServiceSolicitationUuids => {
+                combinator::complete(multi::many0(Uuid16::parse_le))(data)
+                    .map(|(_res, uuids)| {
+                        uuids
+                            .into_iter()
+                            .map(|uuid| {
+                                SERVICE_IDS
+                                    .get(&uuid)
+                                    .map(|name| format!("{:?} ({name})", uuid))
+                                    .unwrap_or_else(|| format!("{:?}", uuid))
+                            })
+                            .join(", ")
+                    })
+                    .ok()
+            }
+            Self::CompleteListOf32BitServiceClassUuids
+            | Self::IncompleteListOf32BitServiceClassUuids
+            | Self::ListOf32BitServiceSolicitationUuids => {
+                combinator::complete(multi::many0(Uuid32::parse))(data)
+                    .map(|(_res, uuids)| uuids.into_iter().map(|u| format!("{:?}", u)).join(", "))
+                    .ok()
+            }
+            Self::CompleteListOf128BitServiceClassUuids
+            | Self::IncompleteListOf128BitServiceClassUuids
+            | Self::ListOf128BitServiceSolicitationUuids => {
+                combinator::complete(multi::many0(Uuid128::parse_le))(data)
+                    .map(|(_res, uuids)| uuids.into_iter().map(|u| format!("{:?}", u)).join(", "))
+                    .ok()
+            }
+            Self::ServiceData16BitUuid => Uuid16::parse_le(data)
+                .map(|(rem, uuid)| {
+                    format!(
+                        "service={:?}, data={}",
+                        SERVICE_IDS
+                            .get(&uuid)
+                            .map(|name| format!("{:?} ({name})", uuid))
+                            .unwrap_or_else(|| format!("{:?}", uuid)),
+                        hex::encode_upper(rem)
+                    )
+                })
+                .ok(),
+            Self::ServiceData32BitUuid => Uuid32::parse(data)
+                .map(|(rem, uuid)| format!("service={:?}, data={}", uuid, hex::encode_upper(rem)))
+                .ok(),
+            Self::ServiceData128BitUuid => Uuid128::parse_le(data)
+                .map(|(rem, uuid)| format!("service={:?}, data={}", uuid, hex::encode_upper(rem)))
+                .ok(),
+            Self::ShortenedLocalName | Self::CompleteLocalName => {
+                std::str::from_utf8(data).ok().map(|s| format!("\"{}\"", s))
+            }
+            Self::TxPowerLevel => {
+                let (_, tx) =
+                    combinator::complete(number::complete::i8::<_, nom::error::Error<_>>)(data)
+                        .ok()?;
+
+                Some(tx.to_string())
+            }
+            Self::ManufacturerSpecificData => {
+                let (rem, id) = Uuid16::parse_le(data).ok()?;
+                Some(format!(
+                    "company={}, data=0x{}",
+                    COMPANY_IDS
+                        .get(&id)
+                        .map(|s| s.to_string())
+                        .unwrap_or_else(|| format!("{:?}", id)),
+                    hex::encode_upper(rem)
+                ))
+            }
+            _ => None,
+        }
+    }
+}
+
+impl fmt::Display for CommonDataType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            CommonDataType::Flags => write!(f, "Flags"),
+            CommonDataType::IncompleteListOf16BitServiceClassUuids => {
+                write!(f, "Incomplete List of 16-bit Service Class UUIDs")
+            }
+            CommonDataType::CompleteListOf16BitServiceClassUuids => {
+                write!(f, "Complete List of 16-bit Service Class UUIDs")
+            }
+            CommonDataType::IncompleteListOf32BitServiceClassUuids => {
+                write!(f, "Incomplete List of 32-bit Service Class UUIDs")
+            }
+            CommonDataType::CompleteListOf32BitServiceClassUuids => {
+                write!(f, "Complete List of 32-bit Service Class UUIDs")
+            }
+            CommonDataType::ListOf16BitServiceSolicitationUuids => {
+                write!(f, "List of 16-bit Service Solicitation UUIDs")
+            }
+            CommonDataType::ListOf32BitServiceSolicitationUuids => {
+                write!(f, "List of 32-bit Service Solicitation UUIDs")
+            }
+            CommonDataType::ListOf128BitServiceSolicitationUuids => {
+                write!(f, "List of 128-bit Service Solicitation UUIDs")
+            }
+            CommonDataType::IncompleteListOf128BitServiceClassUuids => {
+                write!(f, "Incomplete List of 128-bit Service Class UUIDs")
+            }
+            CommonDataType::CompleteListOf128BitServiceClassUuids => {
+                write!(f, "Complete List of 128-bit Service Class UUIDs")
+            }
+            CommonDataType::ShortenedLocalName => write!(f, "Shortened Local Name"),
+            CommonDataType::CompleteLocalName => write!(f, "Complete Local Name"),
+            CommonDataType::TxPowerLevel => write!(f, "TX Power Level"),
+            CommonDataType::ClassOfDevice => write!(f, "Class of Device"),
+            CommonDataType::SimplePairingHashC192 => {
+                write!(f, "Simple Pairing Hash C-192")
+            }
+            CommonDataType::SimplePairingHashC256 => {
+                write!(f, "Simple Pairing Hash C 256")
+            }
+            CommonDataType::SimplePairingRandomizerR192 => {
+                write!(f, "Simple Pairing Randomizer R-192")
+            }
+            CommonDataType::SimplePairingRandomizerR256 => {
+                write!(f, "Simple Pairing Randomizer R 256")
+            }
+            CommonDataType::DeviceId => write!(f, "Device Id"),
+            CommonDataType::SecurityManagerTkValue => {
+                write!(f, "Security Manager TK Value")
+            }
+            CommonDataType::SecurityManagerOutOfBandFlags => {
+                write!(f, "Security Manager Out of Band Flags")
+            }
+            CommonDataType::PeripheralConnectionIntervalRange => {
+                write!(f, "Peripheral Connection Interval Range")
+            }
+            CommonDataType::ServiceData16BitUuid => {
+                write!(f, "Service Data 16-bit UUID")
+            }
+            CommonDataType::ServiceData32BitUuid => {
+                write!(f, "Service Data 32-bit UUID")
+            }
+            CommonDataType::ServiceData128BitUuid => {
+                write!(f, "Service Data 128-bit UUID")
+            }
+            CommonDataType::PublicTargetAddress => write!(f, "Public Target Address"),
+            CommonDataType::RandomTargetAddress => write!(f, "Random Target Address"),
+            CommonDataType::Appearance => write!(f, "Appearance"),
+            CommonDataType::AdvertisingInterval => write!(f, "Advertising Interval"),
+            CommonDataType::LeBluetoothDeviceAddress => {
+                write!(f, "LE Bluetooth Device Address")
+            }
+            CommonDataType::LeRole => write!(f, "LE Role"),
+            CommonDataType::LeSecureConnectionsConfirmationValue => {
+                write!(f, "LE Secure Connections Confirmation Value")
+            }
+            CommonDataType::LeSecureConnectionsRandomValue => {
+                write!(f, "LE Secure Connections Random Value")
+            }
+            CommonDataType::LeSupportedFeatures => write!(f, "LE Supported Features"),
+            CommonDataType::Uri => write!(f, "URI"),
+            CommonDataType::IndoorPositioning => write!(f, "Indoor Positioning"),
+            CommonDataType::TransportDiscoveryData => {
+                write!(f, "Transport Discovery Data")
+            }
+            CommonDataType::ChannelMapUpdateIndication => {
+                write!(f, "Channel Map Update Indication")
+            }
+            CommonDataType::PbAdv => write!(f, "PB-ADV"),
+            CommonDataType::MeshMessage => write!(f, "Mesh Message"),
+            CommonDataType::MeshBeacon => write!(f, "Mesh Beacon"),
+            CommonDataType::BigInfo => write!(f, "BIGIInfo"),
+            CommonDataType::BroadcastCode => write!(f, "Broadcast Code"),
+            CommonDataType::ResolvableSetIdentifier => {
+                write!(f, "Resolvable Set Identifier")
+            }
+            CommonDataType::AdvertisingIntervalLong => {
+                write!(f, "Advertising Interval Long")
+            }
+            CommonDataType::ThreeDInformationData => write!(f, "3D Information Data"),
+            CommonDataType::ManufacturerSpecificData => {
+                write!(f, "Manufacturer Specific Data")
+            }
+        }
+    }
+}
+
+/// Accumulates advertisement data to broadcast on a [crate::wrapper::device::Device].
+#[derive(Debug, Clone, Default)]
+pub struct AdvertisementDataBuilder {
+    encoded_data: Vec<u8>,
+}
+
+impl AdvertisementDataBuilder {
+    /// Returns a new, empty instance.
+    pub fn new() -> Self {
+        Self {
+            encoded_data: Vec::new(),
+        }
+    }
+
+    /// Append advertising data to the builder.
+    ///
+    /// Returns an error if the data cannot be appended.
+    pub fn append(
+        &mut self,
+        type_code: impl Into<CommonDataTypeCode>,
+        data: &[u8],
+    ) -> Result<(), AdvertisementDataBuilderError> {
+        self.encoded_data.push(
+            data.len()
+                .try_into()
+                .ok()
+                .and_then(|len: u8| len.checked_add(1))
+                .ok_or(AdvertisementDataBuilderError::DataTooLong)?,
+        );
+        self.encoded_data.push(type_code.into().0);
+        self.encoded_data.extend_from_slice(data);
+
+        Ok(())
+    }
+
+    pub(crate) fn into_bytes(self) -> Vec<u8> {
+        self.encoded_data
+    }
+}
+
+/// Errors that can occur when building advertisement data with [AdvertisementDataBuilder].
+#[derive(Debug, PartialEq, Eq, thiserror::Error)]
+pub enum AdvertisementDataBuilderError {
+    /// The provided adv data is too long to be encoded
+    #[error("Data too long")]
+    DataTooLong,
+}
+
+#[derive(PartialEq, Eq, strum_macros::EnumIter)]
+#[allow(missing_docs)]
+/// Features in the Flags AD
+pub enum Flags {
+    LeLimited,
+    LeDiscoverable,
+    NoBrEdr,
+    BrEdrController,
+    BrEdrHost,
+}
+
+impl fmt::Debug for Flags {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.short_name())
+    }
+}
+
+impl Flags {
+    /// Iterates over the flags that are present in the provided `flags` bytes.
+    pub fn matching(flags: &[u8]) -> impl Iterator<Item = Self> + '_ {
+        // The encoding is not clear from the spec: do we look at the first byte? or the last?
+        // In practice it's only one byte.
+        let first_byte = flags.first().unwrap_or(&0_u8);
+
+        Self::iter().filter(move |f| {
+            let mask = match f {
+                Flags::LeLimited => 0x01_u8,
+                Flags::LeDiscoverable => 0x02,
+                Flags::NoBrEdr => 0x04,
+                Flags::BrEdrController => 0x08,
+                Flags::BrEdrHost => 0x10,
+            };
+
+            mask & first_byte > 0
+        })
+    }
+
+    /// An abbreviated form of the flag name.
+    ///
+    /// See [Flags::name] for the full name.
+    pub fn short_name(&self) -> &'static str {
+        match self {
+            Flags::LeLimited => "LE Limited",
+            Flags::LeDiscoverable => "LE General",
+            Flags::NoBrEdr => "No BR/EDR",
+            Flags::BrEdrController => "BR/EDR C",
+            Flags::BrEdrHost => "BR/EDR H",
+        }
+    }
+
+    /// The human-readable name of the flag.
+    ///
+    /// See [Flags::short_name] for a shorter string for use if compactness is important.
+    pub fn name(&self) -> &'static str {
+        match self {
+            Flags::LeLimited => "LE Limited Discoverable Mode",
+            Flags::LeDiscoverable => "LE General Discoverable Mode",
+            Flags::NoBrEdr => "BR/EDR Not Supported",
+            Flags::BrEdrController => "Simultaneous LE and BR/EDR (Controller)",
+            Flags::BrEdrHost => "Simultaneous LE and BR/EDR (Host)",
+        }
+    }
+}
diff --git a/rust/src/lib.rs b/rust/src/lib.rs
new file mode 100644
index 0000000..73001e6
--- /dev/null
+++ b/rust/src/lib.rs
@@ -0,0 +1,31 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Rust API for [Bumble](https://github.com/google/bumble).
+//!
+//! Bumble is a userspace Bluetooth stack that works with more or less anything that uses HCI. This
+//! could be physical Bluetooth USB dongles, netsim, HCI proxied over a network from some device
+//! elsewhere, etc.
+//!
+//! It also does not restrict what you can do with Bluetooth the way that OS Bluetooth APIs
+//! typically do, making it good for prototyping, experimentation, test tools, etc.
+//!
+//! Bumble is primarily written in Python. Rust types that wrap the Python API, which is currently
+//! the bulk of the code, are in the [wrapper] module.
+
+#![deny(missing_docs, unsafe_code)]
+
+pub mod wrapper;
+
+pub mod adv;
diff --git a/rust/src/wrapper/assigned_numbers/mod.rs b/rust/src/wrapper/assigned_numbers/mod.rs
new file mode 100644
index 0000000..becdc11
--- /dev/null
+++ b/rust/src/wrapper/assigned_numbers/mod.rs
@@ -0,0 +1,53 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Assigned numbers from the Bluetooth spec.
+
+use crate::wrapper::core::Uuid16;
+use lazy_static::lazy_static;
+use pyo3::{
+    intern,
+    types::{PyDict, PyModule},
+    PyResult, Python,
+};
+use std::collections;
+
+mod services;
+
+pub use services::SERVICE_IDS;
+
+lazy_static! {
+    /// Assigned company IDs
+    pub static ref COMPANY_IDS: collections::HashMap<Uuid16, String> = load_company_ids()
+    .expect("Could not load company ids -- are Bumble's Python sources available?");
+
+}
+
+fn load_company_ids() -> PyResult<collections::HashMap<Uuid16, String>> {
+    // this takes about 4ms on a fast machine -- slower than constructing in rust, but not slow
+    // enough to worry about
+    Python::with_gil(|py| {
+        PyModule::import(py, intern!(py, "bumble.company_ids"))?
+            .getattr(intern!(py, "COMPANY_IDENTIFIERS"))?
+            .downcast::<PyDict>()?
+            .into_iter()
+            .map(|(k, v)| {
+                Ok((
+                    Uuid16::from_be_bytes(k.extract::<u16>()?.to_be_bytes()),
+                    v.str()?.to_str()?.to_string(),
+                ))
+            })
+            .collect::<PyResult<collections::HashMap<_, _>>>()
+    })
+}
diff --git a/rust/src/wrapper/assigned_numbers/services.rs b/rust/src/wrapper/assigned_numbers/services.rs
new file mode 100644
index 0000000..da1c992
--- /dev/null
+++ b/rust/src/wrapper/assigned_numbers/services.rs
@@ -0,0 +1,82 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Assigned service IDs
+
+use crate::wrapper::core::Uuid16;
+use lazy_static::lazy_static;
+use std::collections;
+
+lazy_static! {
+    /// Assigned service IDs
+    pub static ref SERVICE_IDS: collections::HashMap<Uuid16, &'static str> = [
+        (0x1800_u16, "Generic Access"),
+        (0x1801, "Generic Attribute"),
+        (0x1802, "Immediate Alert"),
+        (0x1803, "Link Loss"),
+        (0x1804, "TX Power"),
+        (0x1805, "Current Time"),
+        (0x1806, "Reference Time Update"),
+        (0x1807, "Next DST Change"),
+        (0x1808, "Glucose"),
+        (0x1809, "Health Thermometer"),
+        (0x180A, "Device Information"),
+        (0x180D, "Heart Rate"),
+        (0x180E, "Phone Alert Status"),
+        (0x180F, "Battery"),
+        (0x1810, "Blood Pressure"),
+        (0x1811, "Alert Notification"),
+        (0x1812, "Human Interface Device"),
+        (0x1813, "Scan Parameters"),
+        (0x1814, "Running Speed and Cadence"),
+        (0x1815, "Automation IO"),
+        (0x1816, "Cycling Speed and Cadence"),
+        (0x1818, "Cycling Power"),
+        (0x1819, "Location and Navigation"),
+        (0x181A, "Environmental Sensing"),
+        (0x181B, "Body Composition"),
+        (0x181C, "User Data"),
+        (0x181D, "Weight Scale"),
+        (0x181E, "Bond Management"),
+        (0x181F, "Continuous Glucose Monitoring"),
+        (0x1820, "Internet Protocol Support"),
+        (0x1821, "Indoor Positioning"),
+        (0x1822, "Pulse Oximeter"),
+        (0x1823, "HTTP Proxy"),
+        (0x1824, "Transport Discovery"),
+        (0x1825, "Object Transfer"),
+        (0x1826, "Fitness Machine"),
+        (0x1827, "Mesh Provisioning"),
+        (0x1828, "Mesh Proxy"),
+        (0x1829, "Reconnection Configuration"),
+        (0x183A, "Insulin Delivery"),
+        (0x183B, "Binary Sensor"),
+        (0x183C, "Emergency Configuration"),
+        (0x183E, "Physical Activity Monitor"),
+        (0x1843, "Audio Input Control"),
+        (0x1844, "Volume Control"),
+        (0x1845, "Volume Offset Control"),
+        (0x1846, "Coordinated Set Identification Service"),
+        (0x1847, "Device Time"),
+        (0x1848, "Media Control Service"),
+        (0x1849, "Generic Media Control Service"),
+        (0x184A, "Constant Tone Extension"),
+        (0x184B, "Telephone Bearer Service"),
+        (0x184C, "Generic Telephone Bearer Service"),
+        (0x184D, "Microphone Control"),
+    ]
+    .into_iter()
+    .map(|(num, name)| (Uuid16::from_le_bytes(num.to_le_bytes()), name))
+    .collect();
+}
diff --git a/rust/src/wrapper/core.rs b/rust/src/wrapper/core.rs
new file mode 100644
index 0000000..a55760d
--- /dev/null
+++ b/rust/src/wrapper/core.rs
@@ -0,0 +1,196 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Core types
+
+use crate::adv::CommonDataTypeCode;
+use lazy_static::lazy_static;
+use nom::{bytes, combinator};
+use pyo3::{intern, PyObject, PyResult, Python};
+use std::fmt;
+
+lazy_static! {
+    static ref BASE_UUID: [u8; 16] = hex::decode("0000000000001000800000805F9B34FB")
+        .unwrap()
+        .try_into()
+        .unwrap();
+}
+
+/// A type code and data pair from an advertisement
+pub type AdvertisementDataUnit = (CommonDataTypeCode, Vec<u8>);
+
+/// Contents of an advertisement
+pub struct AdvertisingData(pub(crate) PyObject);
+
+impl AdvertisingData {
+    /// Data units in the advertisement contents
+    pub fn data_units(&self) -> PyResult<Vec<AdvertisementDataUnit>> {
+        Python::with_gil(|py| {
+            let list = self.0.getattr(py, intern!(py, "ad_structures"))?;
+
+            list.as_ref(py)
+                .iter()?
+                .collect::<Result<Vec<_>, _>>()?
+                .into_iter()
+                .map(|tuple| {
+                    let type_code = tuple
+                        .call_method1(intern!(py, "__getitem__"), (0,))?
+                        .extract::<u8>()?
+                        .into();
+                    let data = tuple
+                        .call_method1(intern!(py, "__getitem__"), (1,))?
+                        .extract::<Vec<u8>>()?;
+                    Ok((type_code, data))
+                })
+                .collect::<Result<Vec<_>, _>>()
+        })
+    }
+}
+
+/// 16-bit UUID
+#[derive(PartialEq, Eq, Hash)]
+pub struct Uuid16 {
+    /// Big-endian bytes
+    uuid: [u8; 2],
+}
+
+impl Uuid16 {
+    /// Construct a UUID from little-endian bytes
+    pub fn from_le_bytes(mut bytes: [u8; 2]) -> Self {
+        bytes.reverse();
+        Self::from_be_bytes(bytes)
+    }
+
+    /// Construct a UUID from big-endian bytes
+    pub fn from_be_bytes(bytes: [u8; 2]) -> Self {
+        Self { uuid: bytes }
+    }
+
+    /// The UUID in big-endian bytes form
+    pub fn as_be_bytes(&self) -> [u8; 2] {
+        self.uuid
+    }
+
+    /// The UUID in little-endian bytes form
+    pub fn as_le_bytes(&self) -> [u8; 2] {
+        let mut uuid = self.uuid;
+        uuid.reverse();
+        uuid
+    }
+
+    pub(crate) fn parse_le(input: &[u8]) -> nom::IResult<&[u8], Self> {
+        combinator::map_res(bytes::complete::take(2_usize), |b: &[u8]| {
+            b.try_into().map(|mut uuid: [u8; 2]| {
+                uuid.reverse();
+                Self { uuid }
+            })
+        })(input)
+    }
+}
+
+impl fmt::Debug for Uuid16 {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "UUID-16:{}", hex::encode_upper(self.uuid))
+    }
+}
+
+/// 32-bit UUID
+#[derive(PartialEq, Eq, Hash)]
+pub struct Uuid32 {
+    /// Big-endian bytes
+    uuid: [u8; 4],
+}
+
+impl Uuid32 {
+    /// The UUID in big-endian bytes form
+    pub fn as_bytes(&self) -> [u8; 4] {
+        self.uuid
+    }
+
+    pub(crate) fn parse(input: &[u8]) -> nom::IResult<&[u8], Self> {
+        combinator::map_res(bytes::complete::take(4_usize), |b: &[u8]| {
+            b.try_into().map(|mut uuid: [u8; 4]| {
+                uuid.reverse();
+                Self { uuid }
+            })
+        })(input)
+    }
+}
+
+impl fmt::Debug for Uuid32 {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "UUID-32:{}", hex::encode_upper(self.uuid))
+    }
+}
+
+impl From<Uuid16> for Uuid32 {
+    fn from(value: Uuid16) -> Self {
+        let mut uuid = [0; 4];
+        uuid[2..].copy_from_slice(&value.uuid);
+        Self { uuid }
+    }
+}
+
+/// 128-bit UUID
+#[derive(PartialEq, Eq, Hash)]
+pub struct Uuid128 {
+    /// Big-endian bytes
+    uuid: [u8; 16],
+}
+
+impl Uuid128 {
+    /// The UUID in big-endian bytes form
+    pub fn as_bytes(&self) -> [u8; 16] {
+        self.uuid
+    }
+
+    pub(crate) fn parse_le(input: &[u8]) -> nom::IResult<&[u8], Self> {
+        combinator::map_res(bytes::complete::take(16_usize), |b: &[u8]| {
+            b.try_into().map(|mut uuid: [u8; 16]| {
+                uuid.reverse();
+                Self { uuid }
+            })
+        })(input)
+    }
+}
+
+impl fmt::Debug for Uuid128 {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "{}-{}-{}-{}-{}",
+            hex::encode_upper(&self.uuid[..4]),
+            hex::encode_upper(&self.uuid[4..6]),
+            hex::encode_upper(&self.uuid[6..8]),
+            hex::encode_upper(&self.uuid[8..10]),
+            hex::encode_upper(&self.uuid[10..])
+        )
+    }
+}
+
+impl From<Uuid16> for Uuid128 {
+    fn from(value: Uuid16) -> Self {
+        let mut uuid = *BASE_UUID;
+        uuid[2..4].copy_from_slice(&value.uuid);
+        Self { uuid }
+    }
+}
+
+impl From<Uuid32> for Uuid128 {
+    fn from(value: Uuid32) -> Self {
+        let mut uuid = *BASE_UUID;
+        uuid[..4].copy_from_slice(&value.uuid);
+        Self { uuid }
+    }
+}
diff --git a/rust/src/wrapper/device.rs b/rust/src/wrapper/device.rs
new file mode 100644
index 0000000..d635754
--- /dev/null
+++ b/rust/src/wrapper/device.rs
@@ -0,0 +1,248 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Devices and connections to them
+
+use crate::{
+    adv::AdvertisementDataBuilder,
+    wrapper::{
+        core::AdvertisingData,
+        gatt_client::{ProfileServiceProxy, ServiceProxy},
+        hci::Address,
+        transport::{Sink, Source},
+        ClosureCallback,
+    },
+};
+use pyo3::types::PyDict;
+use pyo3::{intern, types::PyModule, PyObject, PyResult, Python, ToPyObject};
+use std::path;
+
+/// A device that can send/receive HCI frames.
+#[derive(Clone)]
+pub struct Device(PyObject);
+
+impl Device {
+    /// Create a Device per the provided file configured to communicate with a controller through an HCI source/sink
+    pub fn from_config_file_with_hci(
+        device_config: &path::Path,
+        source: Source,
+        sink: Sink,
+    ) -> PyResult<Self> {
+        Python::with_gil(|py| {
+            PyModule::import(py, intern!(py, "bumble.device"))?
+                .getattr(intern!(py, "Device"))?
+                .call_method1(
+                    intern!(py, "from_config_file_with_hci"),
+                    (device_config, source.0, sink.0),
+                )
+                .map(|any| Self(any.into()))
+        })
+    }
+
+    /// Create a Device configured to communicate with a controller through an HCI source/sink
+    pub fn with_hci(name: &str, address: &str, source: Source, sink: Sink) -> PyResult<Self> {
+        Python::with_gil(|py| {
+            PyModule::import(py, intern!(py, "bumble.device"))?
+                .getattr(intern!(py, "Device"))?
+                .call_method1(intern!(py, "with_hci"), (name, address, source.0, sink.0))
+                .map(|any| Self(any.into()))
+        })
+    }
+
+    /// Turn the device on
+    pub async fn power_on(&self) -> PyResult<()> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method0(py, intern!(py, "power_on"))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+
+    /// Connect to a peer
+    pub async fn connect(&self, peer_addr: &str) -> PyResult<Connection> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method1(py, intern!(py, "connect"), (peer_addr,))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(Connection)
+    }
+
+    /// Start scanning
+    pub async fn start_scanning(&self, filter_duplicates: bool) -> PyResult<()> {
+        Python::with_gil(|py| {
+            let kwargs = PyDict::new(py);
+            kwargs.set_item("filter_duplicates", filter_duplicates)?;
+            self.0
+                .call_method(py, intern!(py, "start_scanning"), (), Some(kwargs))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+
+    /// Register a callback to be called for each advertisement
+    pub fn on_advertisement(
+        &mut self,
+        callback: impl Fn(Python, Advertisement) -> PyResult<()> + Send + 'static,
+    ) -> PyResult<()> {
+        let boxed = ClosureCallback::new(move |py, args, _kwargs| {
+            callback(py, Advertisement(args.get_item(0)?.into()))
+        });
+
+        Python::with_gil(|py| {
+            self.0
+                .call_method1(py, intern!(py, "add_listener"), ("advertisement", boxed))
+        })
+        .map(|_| ())
+    }
+
+    /// Set the advertisement data to be used when [Device::start_advertising] is called.
+    pub fn set_advertising_data(&mut self, adv_data: AdvertisementDataBuilder) -> PyResult<()> {
+        Python::with_gil(|py| {
+            self.0.setattr(
+                py,
+                intern!(py, "advertising_data"),
+                adv_data.into_bytes().as_slice(),
+            )
+        })
+        .map(|_| ())
+    }
+
+    /// Start advertising the data set with [Device.set_advertisement].
+    pub async fn start_advertising(&mut self, auto_restart: bool) -> PyResult<()> {
+        Python::with_gil(|py| {
+            let kwargs = PyDict::new(py);
+            kwargs.set_item("auto_restart", auto_restart)?;
+
+            self.0
+                .call_method(py, intern!(py, "start_advertising"), (), Some(kwargs))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+
+    /// Stop advertising.
+    pub async fn stop_advertising(&mut self) -> PyResult<()> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method0(py, intern!(py, "stop_advertising"))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+}
+
+/// A connection to a remote device.
+pub struct Connection(PyObject);
+
+/// The other end of a connection
+pub struct Peer(PyObject);
+
+impl Peer {
+    /// Wrap a [Connection] in a Peer
+    pub fn new(conn: Connection) -> PyResult<Self> {
+        Python::with_gil(|py| {
+            PyModule::import(py, intern!(py, "bumble.device"))?
+                .getattr(intern!(py, "Peer"))?
+                .call1((conn.0,))
+                .map(|obj| Self(obj.into()))
+        })
+    }
+
+    /// Populates the peer's cache of services.
+    ///
+    /// Returns the discovered services.
+    pub async fn discover_services(&mut self) -> PyResult<Vec<ServiceProxy>> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method0(py, intern!(py, "discover_services"))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .and_then(|list| {
+            Python::with_gil(|py| {
+                list.as_ref(py)
+                    .iter()?
+                    .map(|r| r.map(|h| ServiceProxy(h.to_object(py))))
+                    .collect()
+            })
+        })
+    }
+
+    /// Returns a snapshot of the Services currently in the peer's cache
+    pub fn services(&self) -> PyResult<Vec<ServiceProxy>> {
+        Python::with_gil(|py| {
+            self.0
+                .getattr(py, intern!(py, "services"))?
+                .as_ref(py)
+                .iter()?
+                .map(|r| r.map(|h| ServiceProxy(h.to_object(py))))
+                .collect()
+        })
+    }
+
+    /// Build a [ProfileServiceProxy] for the specified type.
+    /// [Peer::discover_services] or some other means of populating the Peer's service cache must be
+    /// called first, or the required service won't be found.
+    pub fn create_service_proxy<P: ProfileServiceProxy>(&self) -> PyResult<Option<P>> {
+        Python::with_gil(|py| {
+            let module = py.import(P::PROXY_CLASS_MODULE)?;
+            let class = module.getattr(P::PROXY_CLASS_NAME)?;
+            self.0
+                .call_method1(py, intern!(py, "create_service_proxy"), (class,))
+                .map(|obj| {
+                    if obj.is_none(py) {
+                        None
+                    } else {
+                        Some(P::wrap(obj))
+                    }
+                })
+        })
+    }
+}
+
+/// A BLE advertisement
+pub struct Advertisement(PyObject);
+
+impl Advertisement {
+    /// Address that sent the advertisement
+    pub fn address(&self) -> PyResult<Address> {
+        Python::with_gil(|py| self.0.getattr(py, intern!(py, "address")).map(Address))
+    }
+
+    /// Returns true if the advertisement is connectable
+    pub fn is_connectable(&self) -> PyResult<bool> {
+        Python::with_gil(|py| {
+            self.0
+                .getattr(py, intern!(py, "is_connectable"))?
+                .extract::<bool>(py)
+        })
+    }
+
+    /// RSSI of the advertisement
+    pub fn rssi(&self) -> PyResult<i8> {
+        Python::with_gil(|py| self.0.getattr(py, intern!(py, "rssi"))?.extract::<i8>(py))
+    }
+
+    /// Data in the advertisement
+    pub fn data(&self) -> PyResult<AdvertisingData> {
+        Python::with_gil(|py| self.0.getattr(py, intern!(py, "data")).map(AdvertisingData))
+    }
+}
diff --git a/rust/src/wrapper/gatt_client.rs b/rust/src/wrapper/gatt_client.rs
new file mode 100644
index 0000000..aff1cb2
--- /dev/null
+++ b/rust/src/wrapper/gatt_client.rs
@@ -0,0 +1,79 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! GATT client support
+
+use crate::wrapper::ClosureCallback;
+use pyo3::types::PyTuple;
+use pyo3::{intern, PyObject, PyResult, Python};
+
+/// A GATT service on a remote device
+pub struct ServiceProxy(pub(crate) PyObject);
+
+impl ServiceProxy {
+    /// Discover the characteristics in this service.
+    ///
+    /// Populates an internal cache of characteristics in this service.
+    pub async fn discover_characteristics(&mut self) -> PyResult<()> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method0(py, intern!(py, "discover_characteristics"))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+}
+
+/// A GATT characteristic on a remote device
+pub struct CharacteristicProxy(pub(crate) PyObject);
+
+impl CharacteristicProxy {
+    /// Subscribe to changes to the characteristic, executing `callback` for each new value
+    pub async fn subscribe(
+        &mut self,
+        callback: impl Fn(Python, &PyTuple) -> PyResult<()> + Send + 'static,
+    ) -> PyResult<()> {
+        let boxed = ClosureCallback::new(move |py, args, _kwargs| callback(py, args));
+
+        Python::with_gil(|py| {
+            self.0
+                .call_method1(py, intern!(py, "subscribe"), (boxed,))
+                .and_then(|obj| pyo3_asyncio::tokio::into_future(obj.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+
+    /// Read the current value of the characteristic
+    pub async fn read_value(&self) -> PyResult<PyObject> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method0(py, intern!(py, "read_value"))
+                .and_then(|obj| pyo3_asyncio::tokio::into_future(obj.as_ref(py)))
+        })?
+        .await
+    }
+}
+
+/// Equivalent to the Python `ProfileServiceProxy`.
+pub trait ProfileServiceProxy {
+    /// The module containing the proxy class
+    const PROXY_CLASS_MODULE: &'static str;
+    /// The module class name
+    const PROXY_CLASS_NAME: &'static str;
+
+    /// Wrap a PyObject in the Rust wrapper type
+    fn wrap(obj: PyObject) -> Self;
+}
diff --git a/rust/src/wrapper/hci.rs b/rust/src/wrapper/hci.rs
new file mode 100644
index 0000000..48f7dc1
--- /dev/null
+++ b/rust/src/wrapper/hci.rs
@@ -0,0 +1,112 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! HCI
+
+use itertools::Itertools as _;
+use pyo3::{exceptions::PyException, intern, types::PyModule, PyErr, PyObject, PyResult, Python};
+
+/// A Bluetooth address
+pub struct Address(pub(crate) PyObject);
+
+impl Address {
+    /// The type of address
+    pub fn address_type(&self) -> PyResult<AddressType> {
+        Python::with_gil(|py| {
+            let addr_type = self
+                .0
+                .getattr(py, intern!(py, "address_type"))?
+                .extract::<u32>(py)?;
+
+            let module = PyModule::import(py, intern!(py, "bumble.hci"))?;
+            let klass = module.getattr(intern!(py, "Address"))?;
+
+            if addr_type
+                == klass
+                    .getattr(intern!(py, "PUBLIC_DEVICE_ADDRESS"))?
+                    .extract::<u32>()?
+            {
+                Ok(AddressType::PublicDevice)
+            } else if addr_type
+                == klass
+                    .getattr(intern!(py, "RANDOM_DEVICE_ADDRESS"))?
+                    .extract::<u32>()?
+            {
+                Ok(AddressType::RandomDevice)
+            } else if addr_type
+                == klass
+                    .getattr(intern!(py, "PUBLIC_IDENTITY_ADDRESS"))?
+                    .extract::<u32>()?
+            {
+                Ok(AddressType::PublicIdentity)
+            } else if addr_type
+                == klass
+                    .getattr(intern!(py, "RANDOM_IDENTITY_ADDRESS"))?
+                    .extract::<u32>()?
+            {
+                Ok(AddressType::RandomIdentity)
+            } else {
+                Err(PyErr::new::<PyException, _>("Invalid address type"))
+            }
+        })
+    }
+
+    /// True if the address is static
+    pub fn is_static(&self) -> PyResult<bool> {
+        Python::with_gil(|py| {
+            self.0
+                .getattr(py, intern!(py, "is_static"))?
+                .extract::<bool>(py)
+        })
+    }
+
+    /// True if the address is resolvable
+    pub fn is_resolvable(&self) -> PyResult<bool> {
+        Python::with_gil(|py| {
+            self.0
+                .getattr(py, intern!(py, "is_resolvable"))?
+                .extract::<bool>(py)
+        })
+    }
+
+    /// Address bytes in _little-endian_ format
+    pub fn as_le_bytes(&self) -> PyResult<Vec<u8>> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method0(py, intern!(py, "to_bytes"))?
+                .extract::<Vec<u8>>(py)
+        })
+    }
+
+    /// Address bytes as big-endian colon-separated hex
+    pub fn as_hex(&self) -> PyResult<String> {
+        self.as_le_bytes().map(|bytes| {
+            bytes
+                .into_iter()
+                .rev()
+                .map(|byte| hex::encode_upper([byte]))
+                .join(":")
+        })
+    }
+}
+
+/// BT address types
+#[allow(missing_docs)]
+#[derive(PartialEq, Eq, Debug)]
+pub enum AddressType {
+    PublicDevice,
+    RandomDevice,
+    PublicIdentity,
+    RandomIdentity,
+}
diff --git a/rust/src/wrapper/logging.rs b/rust/src/wrapper/logging.rs
new file mode 100644
index 0000000..141cc04
--- /dev/null
+++ b/rust/src/wrapper/logging.rs
@@ -0,0 +1,27 @@
+//! Bumble & Python logging
+
+use pyo3::types::PyDict;
+use pyo3::{intern, types::PyModule, PyResult, Python};
+use std::env;
+
+/// Returns the uppercased contents of the `BUMBLE_LOGLEVEL` env var, or `default` if it is not present or not UTF-8.
+///
+/// The result could be passed to [py_logging_basic_config] to configure Python's logging
+/// accordingly.
+pub fn bumble_env_logging_level(default: impl Into<String>) -> String {
+    env::var("BUMBLE_LOGLEVEL")
+        .unwrap_or_else(|_| default.into())
+        .to_ascii_uppercase()
+}
+
+/// Call `logging.basicConfig` with the provided logging level
+pub fn py_logging_basic_config(log_level: impl Into<String>) -> PyResult<()> {
+    Python::with_gil(|py| {
+        let kwargs = PyDict::new(py);
+        kwargs.set_item("level", log_level.into())?;
+
+        PyModule::import(py, intern!(py, "logging"))?
+            .call_method(intern!(py, "basicConfig"), (), Some(kwargs))
+            .map(|_| ())
+    })
+}
diff --git a/rust/src/wrapper/mod.rs b/rust/src/wrapper/mod.rs
new file mode 100644
index 0000000..2ab71c3
--- /dev/null
+++ b/rust/src/wrapper/mod.rs
@@ -0,0 +1,92 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Types that wrap the Python API.
+//!
+//! Because mutability, aliasing, etc is all hidden behind Python, the normal Rust rules about
+//! only one mutable reference to one piece of memory, etc, may not hold since using `&mut self`
+//! instead of `&self` is only guided by inspection of the Python source, not the compiler.
+//!
+//! The modules are generally structured to mirror the Python equivalents.
+
+// Re-exported to make it easy for users to depend on the same `PyObject`, etc
+pub use pyo3;
+use pyo3::{
+    prelude::*,
+    types::{PyDict, PyTuple},
+};
+pub use pyo3_asyncio;
+
+pub mod assigned_numbers;
+pub mod core;
+pub mod device;
+pub mod gatt_client;
+pub mod hci;
+pub mod logging;
+pub mod profile;
+pub mod transport;
+
+/// Convenience extensions to [PyObject]
+pub trait PyObjectExt {
+    /// Get a GIL-bound reference
+    fn gil_ref<'py>(&'py self, py: Python<'py>) -> &'py PyAny;
+
+    /// Extract any [FromPyObject] implementation from this value
+    fn extract_with_gil<T>(&self) -> PyResult<T>
+    where
+        T: for<'a> FromPyObject<'a>,
+    {
+        Python::with_gil(|py| self.gil_ref(py).extract::<T>())
+    }
+}
+
+impl PyObjectExt for PyObject {
+    fn gil_ref<'py>(&'py self, py: Python<'py>) -> &'py PyAny {
+        self.as_ref(py)
+    }
+}
+
+/// Wrapper to make Rust closures ([Fn] implementations) callable from Python.
+///
+/// The Python callable form returns a Python `None`.
+#[pyclass(name = "SubscribeCallback")]
+pub(crate) struct ClosureCallback {
+    // can't use generics in a pyclass, so have to box
+    #[allow(clippy::type_complexity)]
+    callback: Box<dyn Fn(Python, &PyTuple, Option<&PyDict>) -> PyResult<()> + Send + 'static>,
+}
+
+impl ClosureCallback {
+    /// Create a new callback around the provided closure
+    pub fn new(
+        callback: impl Fn(Python, &PyTuple, Option<&PyDict>) -> PyResult<()> + Send + 'static,
+    ) -> Self {
+        Self {
+            callback: Box::new(callback),
+        }
+    }
+}
+
+#[pymethods]
+impl ClosureCallback {
+    #[pyo3(signature = (*args, **kwargs))]
+    fn __call__(
+        &self,
+        py: Python<'_>,
+        args: &PyTuple,
+        kwargs: Option<&PyDict>,
+    ) -> PyResult<Py<PyAny>> {
+        (self.callback)(py, args, kwargs).map(|_| py.None())
+    }
+}
diff --git a/rust/src/wrapper/profile.rs b/rust/src/wrapper/profile.rs
new file mode 100644
index 0000000..854ba80
--- /dev/null
+++ b/rust/src/wrapper/profile.rs
@@ -0,0 +1,47 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! GATT profiles
+
+use crate::wrapper::gatt_client::{CharacteristicProxy, ProfileServiceProxy};
+use pyo3::{intern, PyObject, PyResult, Python};
+
+/// Exposes the battery GATT service
+pub struct BatteryServiceProxy(PyObject);
+
+impl BatteryServiceProxy {
+    /// Get the battery level, if available
+    pub fn battery_level(&self) -> PyResult<Option<CharacteristicProxy>> {
+        Python::with_gil(|py| {
+            self.0
+                .getattr(py, intern!(py, "battery_level"))
+                .map(|level| {
+                    if level.is_none(py) {
+                        None
+                    } else {
+                        Some(CharacteristicProxy(level))
+                    }
+                })
+        })
+    }
+}
+
+impl ProfileServiceProxy for BatteryServiceProxy {
+    const PROXY_CLASS_MODULE: &'static str = "bumble.profiles.battery_service";
+    const PROXY_CLASS_NAME: &'static str = "BatteryServiceProxy";
+
+    fn wrap(obj: PyObject) -> Self {
+        Self(obj)
+    }
+}
diff --git a/rust/src/wrapper/transport.rs b/rust/src/wrapper/transport.rs
new file mode 100644
index 0000000..6c9468d
--- /dev/null
+++ b/rust/src/wrapper/transport.rs
@@ -0,0 +1,72 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! HCI packet transport
+
+use pyo3::{intern, types::PyModule, PyObject, PyResult, Python};
+
+/// A source/sink pair for HCI packet I/O.
+///
+/// See <https://google.github.io/bumble/transports/index.html>.
+pub struct Transport(PyObject);
+
+impl Transport {
+    /// Open a new Transport for the provided spec, e.g. `"usb:0"` or `"android-netsim"`.
+    pub async fn open(transport_spec: impl Into<String>) -> PyResult<Self> {
+        Python::with_gil(|py| {
+            PyModule::import(py, intern!(py, "bumble.transport"))?
+                .call_method1(intern!(py, "open_transport"), (transport_spec.into(),))
+                .and_then(pyo3_asyncio::tokio::into_future)
+        })?
+        .await
+        .map(Self)
+    }
+
+    /// Close the transport.
+    pub async fn close(&mut self) -> PyResult<()> {
+        Python::with_gil(|py| {
+            self.0
+                .call_method0(py, intern!(py, "close"))
+                .and_then(|coroutine| pyo3_asyncio::tokio::into_future(coroutine.as_ref(py)))
+        })?
+        .await
+        .map(|_| ())
+    }
+
+    /// Returns the source half of the transport.
+    pub fn source(&self) -> PyResult<Source> {
+        Python::with_gil(|py| self.0.getattr(py, intern!(py, "source"))).map(Source)
+    }
+
+    /// Returns the sink half of the transport.
+    pub fn sink(&self) -> PyResult<Sink> {
+        Python::with_gil(|py| self.0.getattr(py, intern!(py, "sink"))).map(Sink)
+    }
+}
+
+impl Drop for Transport {
+    fn drop(&mut self) {
+        // can't await in a Drop impl, but we can at least spawn a task to do it
+        let obj = self.0.clone();
+        tokio::spawn(async move { Self(obj).close().await });
+    }
+}
+
+/// The source side of a [Transport].
+#[derive(Clone)]
+pub struct Source(pub(crate) PyObject);
+
+/// The sink side of a [Transport].
+#[derive(Clone)]
+pub struct Sink(pub(crate) PyObject);
diff --git a/setup.cfg b/setup.cfg
index 45c7264..a7a09d6 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -24,28 +24,30 @@
 
 [options]
 python_requires = >=3.8
-packages = bumble, bumble.transport, bumble.profiles, bumble.apps, bumble.apps.link_relay, bumble.pandora
+packages = bumble, bumble.transport, bumble.drivers, bumble.profiles, bumble.apps, bumble.apps.link_relay, bumble.pandora, bumble.tools
 package_dir =
     bumble = bumble
     bumble.apps = apps
-include-package-data = True
+    bumble.tools = tools
+include_package_data = True
 install_requires =
+    aiohttp ~= 3.8; platform_system!='Emscripten'
     appdirs >= 1.4
-    click >= 7.1.2; platform_system!='Emscripten'
+    bt-test-interfaces >= 0.0.2
+    click == 8.1.3; platform_system!='Emscripten'
     cryptography == 35; platform_system!='Emscripten'
     grpcio == 1.51.1; platform_system!='Emscripten'
+    humanize >= 4.6.0
     libusb1 >= 2.0.1; platform_system!='Emscripten'
     libusb-package == 1.0.26.1; platform_system!='Emscripten'
     prompt_toolkit >= 3.0.16; platform_system!='Emscripten'
+    prettytable >= 3.6.0
     protobuf >= 3.12.4
     pyee >= 8.2.2
     pyserial-asyncio >= 0.5; platform_system!='Emscripten'
     pyserial >= 3.5; platform_system!='Emscripten'
     pyusb >= 1.2; platform_system!='Emscripten'
     websockets >= 8.1; platform_system!='Emscripten'
-    prettytable >= 3.6.0
-    humanize >= 4.6.0
-    bt-test-interfaces >= 0.0.2
 
 [options.entry_points]
 console_scripts =
@@ -61,7 +63,10 @@
     bumble-usb-probe = bumble.apps.usb_probe:main
     bumble-link-relay = bumble.apps.link_relay.link_relay:main
     bumble-bench = bumble.apps.bench:main
+    bumble-speaker = bumble.apps.speaker.speaker:main
     bumble-pandora-server = bumble.apps.pandora_server:main
+    bumble-rtk-util = bumble.tools.rtk_util:main
+    bumble-rtk-fw-download = bumble.tools.rtk_fw_download:main
 
 [options.package_data]
 * = py.typed, *.pyi
diff --git a/speaker.html b/speaker.html
new file mode 100644
index 0000000..05cc31f
--- /dev/null
+++ b/speaker.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Audio WAV Player</title>
+  </head>
+  <body>
+    <h1>Audio WAV Player</h1>
+    <audio id="audioPlayer" controls>
+      <source src="" type="audio/wav">
+    </audio>
+
+    <script>
+      const audioPlayer = document.getElementById('audioPlayer');
+      const ws = new WebSocket('ws://localhost:8080');
+
+      let mediaSource = new MediaSource();
+      audioPlayer.src = URL.createObjectURL(mediaSource);
+
+      mediaSource.addEventListener('sourceopen', function(event) {
+        const sourceBuffer = mediaSource.addSourceBuffer('audio/wav');
+
+        ws.onmessage = function(event) {
+          sourceBuffer.appendBuffer(event.data);
+        };
+      });
+    </script>
+  </body>
+</html>
diff --git a/tests/codecs_test.py b/tests/codecs_test.py
new file mode 100644
index 0000000..b8affad
--- /dev/null
+++ b/tests/codecs_test.py
@@ -0,0 +1,67 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+import pytest
+from bumble.codecs import AacAudioRtpPacket, BitReader
+
+
+# -----------------------------------------------------------------------------
+def test_reader():
+    reader = BitReader(b'')
+    with pytest.raises(ValueError):
+        reader.read(1)
+
+    reader = BitReader(b'hello')
+    with pytest.raises(ValueError):
+        reader.read(40)
+
+    reader = BitReader(bytes([0xFF]))
+    assert reader.read(1) == 1
+    with pytest.raises(ValueError):
+        reader.read(10)
+
+    reader = BitReader(bytes([0x78]))
+    value = 0
+    for _ in range(8):
+        value = (value << 1) | reader.read(1)
+    assert value == 0x78
+
+    data = bytes([x & 0xFF for x in range(66 * 100)])
+    reader = BitReader(data)
+    value = 0
+    for _ in range(100):
+        for bits in range(1, 33):
+            value = value << bits | reader.read(bits)
+    assert value == int.from_bytes(data, byteorder='big')
+
+
+def test_aac_rtp():
+    # pylint: disable=line-too-long
+    packet_data = bytes.fromhex(
+        '47fc0000b090800300202066000198000de120000000000000000000000000000000000000000000001c'
+    )
+    packet = AacAudioRtpPacket(packet_data)
+    adts = packet.to_adts()
+    assert adts == bytes.fromhex(
+        'fff1508004fffc2066000198000de120000000000000000000000000000000000000000000001c'
+    )
+
+
+# -----------------------------------------------------------------------------
+if __name__ == '__main__':
+    test_reader()
+    test_aac_rtp()
diff --git a/tests/gatt_test.py b/tests/gatt_test.py
index 0652197..dd0277e 100644
--- a/tests/gatt_test.py
+++ b/tests/gatt_test.py
@@ -803,14 +803,14 @@
 # -----------------------------------------------------------------------------
 def test_char_property_to_string():
     # single
-    assert str(Characteristic.Properties(0x01)) == "Properties.BROADCAST"
-    assert str(Characteristic.Properties.BROADCAST) == "Properties.BROADCAST"
+    assert str(Characteristic.Properties(0x01)) == "BROADCAST"
+    assert str(Characteristic.Properties.BROADCAST) == "BROADCAST"
 
     # double
-    assert str(Characteristic.Properties(0x03)) == "Properties.READ|BROADCAST"
+    assert str(Characteristic.Properties(0x03)) == "BROADCAST|READ"
     assert (
         str(Characteristic.Properties.BROADCAST | Characteristic.Properties.READ)
-        == "Properties.READ|BROADCAST"
+        == "BROADCAST|READ"
     )
 
 
@@ -831,6 +831,10 @@
         Characteristic.Properties.from_string("READ,BROADCAST")
         == Characteristic.Properties.BROADCAST | Characteristic.Properties.READ
     )
+    assert (
+        Characteristic.Properties.from_string("BROADCAST|READ")
+        == Characteristic.Properties.BROADCAST | Characteristic.Properties.READ
+    )
 
 
 # -----------------------------------------------------------------------------
@@ -841,7 +845,7 @@
     assert (
         str(e_info.value)
         == """Characteristic.Properties::from_string() error:
-Expected a string containing any of the keys, separated by commas: BROADCAST,READ,WRITE_WITHOUT_RESPONSE,WRITE,NOTIFY,INDICATE,AUTHENTICATED_SIGNED_WRITES,EXTENDED_PROPERTIES
+Expected a string containing any of the keys, separated by , or |: BROADCAST,READ,WRITE_WITHOUT_RESPONSE,WRITE,NOTIFY,INDICATE,AUTHENTICATED_SIGNED_WRITES,EXTENDED_PROPERTIES
 Got: BROADCAST,HELLO"""
     )
 
@@ -866,13 +870,13 @@
     assert (
         str(server.gatt_server)
         == """Service(handle=0x0001, end=0x0005, uuid=UUID-16:1800 (Generic Access))
-CharacteristicDeclaration(handle=0x0002, value_handle=0x0003, uuid=UUID-16:2A00 (Device Name), Properties.READ)
-Characteristic(handle=0x0003, end=0x0003, uuid=UUID-16:2A00 (Device Name), Properties.READ)
-CharacteristicDeclaration(handle=0x0004, value_handle=0x0005, uuid=UUID-16:2A01 (Appearance), Properties.READ)
-Characteristic(handle=0x0005, end=0x0005, uuid=UUID-16:2A01 (Appearance), Properties.READ)
+CharacteristicDeclaration(handle=0x0002, value_handle=0x0003, uuid=UUID-16:2A00 (Device Name), READ)
+Characteristic(handle=0x0003, end=0x0003, uuid=UUID-16:2A00 (Device Name), READ)
+CharacteristicDeclaration(handle=0x0004, value_handle=0x0005, uuid=UUID-16:2A01 (Appearance), READ)
+Characteristic(handle=0x0005, end=0x0005, uuid=UUID-16:2A01 (Appearance), READ)
 Service(handle=0x0006, end=0x0009, uuid=3A657F47-D34F-46B3-B1EC-698E29B6B829)
-CharacteristicDeclaration(handle=0x0007, value_handle=0x0008, uuid=FDB159DB-036C-49E3-B3DB-6325AC750806, Properties.NOTIFY|WRITE|READ)
-Characteristic(handle=0x0008, end=0x0009, uuid=FDB159DB-036C-49E3-B3DB-6325AC750806, Properties.NOTIFY|WRITE|READ)
+CharacteristicDeclaration(handle=0x0007, value_handle=0x0008, uuid=FDB159DB-036C-49E3-B3DB-6325AC750806, READ|WRITE|NOTIFY)
+Characteristic(handle=0x0008, end=0x0009, uuid=FDB159DB-036C-49E3-B3DB-6325AC750806, READ|WRITE|NOTIFY)
 Descriptor(handle=0x0009, type=UUID-16:2902 (Client Characteristic Configuration), value=0000)"""
     )
 
diff --git a/tests/hci_test.py b/tests/hci_test.py
index af68e86..c648592 100644
--- a/tests/hci_test.py
+++ b/tests/hci_test.py
@@ -46,6 +46,7 @@
     HCI_LE_Set_Advertising_Parameters_Command,
     HCI_LE_Set_Default_PHY_Command,
     HCI_LE_Set_Event_Mask_Command,
+    HCI_LE_Set_Extended_Advertising_Enable_Command,
     HCI_LE_Set_Extended_Scan_Parameters_Command,
     HCI_LE_Set_Random_Address_Command,
     HCI_LE_Set_Scan_Enable_Command,
@@ -423,6 +424,25 @@
 
 
 # -----------------------------------------------------------------------------
+def test_HCI_LE_Set_Extended_Advertising_Enable_Command():
+    command = HCI_Packet.from_bytes(
+        bytes.fromhex('0139200e010301050008020600090307000a')
+    )
+    assert command.enable == 1
+    assert command.advertising_handles == [1, 2, 3]
+    assert command.durations == [5, 6, 7]
+    assert command.max_extended_advertising_events == [8, 9, 10]
+
+    command = HCI_LE_Set_Extended_Advertising_Enable_Command(
+        enable=1,
+        advertising_handles=[1, 2, 3],
+        durations=[5, 6, 7],
+        max_extended_advertising_events=[8, 9, 10],
+    )
+    basic_check(command)
+
+
+# -----------------------------------------------------------------------------
 def test_address():
     a = Address('C4:F2:17:1A:1D:BB')
     assert not a.is_public
@@ -478,6 +498,7 @@
     test_HCI_LE_Read_Remote_Features_Command()
     test_HCI_LE_Set_Default_PHY_Command()
     test_HCI_LE_Set_Extended_Scan_Parameters_Command()
+    test_HCI_LE_Set_Extended_Advertising_Enable_Command()
 
 
 # -----------------------------------------------------------------------------
diff --git a/tests/keystore_test.py b/tests/keystore_test.py
new file mode 100644
index 0000000..2e73039
--- /dev/null
+++ b/tests/keystore_test.py
@@ -0,0 +1,179 @@
+# Copyright 2021-2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+import asyncio
+import json
+import logging
+import tempfile
+import os
+
+from bumble.keys import JsonKeyStore, PairingKeys
+
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+
+# -----------------------------------------------------------------------------
+# Tests
+# -----------------------------------------------------------------------------
+
+JSON1 = """
+        {
+            "my_namespace": {
+                "14:7D:DA:4E:53:A8/P": {
+                    "address_type": 0,
+                    "irk": {
+                        "authenticated": false,
+                        "value": "e7b2543b206e4e46b44f9e51dad22bd1"
+                    },
+                    "link_key": {
+                        "authenticated": false,
+                        "value": "0745dd9691e693d9dca740f7d8dfea75"
+                    },
+                    "ltk": {
+                        "authenticated": false,
+                        "value": "d1897ee10016eb1a08e4e037fd54c683"
+                    }
+                }
+            }
+        }
+        """
+
+JSON2 = """
+        {
+            "my_namespace1": {
+            },
+            "my_namespace2": {
+            }
+        }
+        """
+
+JSON3 = """
+        {
+            "my_namespace1": {
+            },
+            "__DEFAULT__": {
+                "14:7D:DA:4E:53:A8/P": {
+                    "address_type": 0,
+                    "irk": {
+                        "authenticated": false,
+                        "value": "e7b2543b206e4e46b44f9e51dad22bd1"
+                    }
+                }
+            }
+        }
+        """
+
+
+# -----------------------------------------------------------------------------
+async def test_basic():
+    with tempfile.NamedTemporaryFile(mode="r+", encoding='utf-8') as file:
+        keystore = JsonKeyStore('my_namespace', file.name)
+        file.write("{}")
+        file.flush()
+
+        keys = await keystore.get_all()
+        assert len(keys) == 0
+
+        keys = PairingKeys()
+        await keystore.update('foo', keys)
+        foo = await keystore.get('foo')
+        assert foo is not None
+        assert foo.ltk is None
+        ltk = bytes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15])
+        keys.ltk = PairingKeys.Key(ltk)
+        await keystore.update('foo', keys)
+        foo = await keystore.get('foo')
+        assert foo is not None
+        assert foo.ltk is not None
+        assert foo.ltk.value == ltk
+
+        file.flush()
+        with open(file.name, "r", encoding="utf-8") as json_file:
+            json_data = json.load(json_file)
+            assert 'my_namespace' in json_data
+            assert 'foo' in json_data['my_namespace']
+            assert 'ltk' in json_data['my_namespace']['foo']
+
+
+# -----------------------------------------------------------------------------
+async def test_parsing():
+    with tempfile.NamedTemporaryFile(mode="w", encoding='utf-8') as file:
+        keystore = JsonKeyStore('my_namespace', file.name)
+        file.write(JSON1)
+        file.flush()
+
+        foo = await keystore.get('14:7D:DA:4E:53:A8/P')
+        assert foo is not None
+        assert foo.ltk.value == bytes.fromhex('d1897ee10016eb1a08e4e037fd54c683')
+
+
+# -----------------------------------------------------------------------------
+async def test_default_namespace():
+    with tempfile.NamedTemporaryFile(mode="w", encoding='utf-8') as file:
+        keystore = JsonKeyStore(None, file.name)
+        file.write(JSON1)
+        file.flush()
+
+        all_keys = await keystore.get_all()
+        assert len(all_keys) == 1
+        name, keys = all_keys[0]
+        assert name == '14:7D:DA:4E:53:A8/P'
+        assert keys.irk.value == bytes.fromhex('e7b2543b206e4e46b44f9e51dad22bd1')
+
+    with tempfile.NamedTemporaryFile(mode="w", encoding='utf-8') as file:
+        keystore = JsonKeyStore(None, file.name)
+        file.write(JSON2)
+        file.flush()
+
+        keys = PairingKeys()
+        ltk = bytes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15])
+        keys.ltk = PairingKeys.Key(ltk)
+        await keystore.update('foo', keys)
+        file.flush()
+        with open(file.name, "r", encoding="utf-8") as json_file:
+            json_data = json.load(json_file)
+            assert '__DEFAULT__' in json_data
+            assert 'foo' in json_data['__DEFAULT__']
+            assert 'ltk' in json_data['__DEFAULT__']['foo']
+
+    with tempfile.NamedTemporaryFile(mode="w", encoding='utf-8') as file:
+        keystore = JsonKeyStore(None, file.name)
+        file.write(JSON3)
+        file.flush()
+
+        all_keys = await keystore.get_all()
+        assert len(all_keys) == 1
+        name, keys = all_keys[0]
+        assert name == '14:7D:DA:4E:53:A8/P'
+        assert keys.irk.value == bytes.fromhex('e7b2543b206e4e46b44f9e51dad22bd1')
+
+
+# -----------------------------------------------------------------------------
+async def run_tests():
+    await test_basic()
+    await test_parsing()
+    await test_default_namespace()
+
+
+# -----------------------------------------------------------------------------
+if __name__ == '__main__':
+    logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'INFO').upper())
+    asyncio.run(run_tests())
diff --git a/tests/self_test.py b/tests/self_test.py
index 1a1a474..4c35045 100644
--- a/tests/self_test.py
+++ b/tests/self_test.py
@@ -21,6 +21,8 @@
 import os
 import pytest
 
+from unittest.mock import MagicMock, patch
+
 from bumble.controller import Controller
 from bumble.core import BT_BR_EDR_TRANSPORT, BT_PERIPHERAL_ROLE, BT_CENTRAL_ROLE
 from bumble.link import LocalLink
@@ -34,6 +36,8 @@
     SMP_CONFIRM_VALUE_FAILED_ERROR,
 )
 from bumble.core import ProtocolError
+from bumble.hci import HCI_AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P_256_TYPE
+from bumble.keys import PairingKeys
 
 
 # -----------------------------------------------------------------------------
@@ -474,6 +478,105 @@
 
 
 # -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_self_smp_over_classic():
+    # Create two devices, each with a controller, attached to the same link
+    two_devices = TwoDevices()
+
+    # Attach listeners
+    two_devices.devices[0].on(
+        'connection', lambda connection: two_devices.on_connection(0, connection)
+    )
+    two_devices.devices[1].on(
+        'connection', lambda connection: two_devices.on_connection(1, connection)
+    )
+
+    # Enable Classic connections
+    two_devices.devices[0].classic_enabled = True
+    two_devices.devices[1].classic_enabled = True
+
+    # Start
+    await two_devices.devices[0].power_on()
+    await two_devices.devices[1].power_on()
+
+    # Connect the two devices
+    await asyncio.gather(
+        two_devices.devices[0].connect(
+            two_devices.devices[1].public_address, transport=BT_BR_EDR_TRANSPORT
+        ),
+        two_devices.devices[1].accept(two_devices.devices[0].public_address),
+    )
+
+    # Check the post conditions
+    assert two_devices.connections[0] is not None
+    assert two_devices.connections[1] is not None
+
+    # Mock connection
+    # TODO: Implement Classic SSP and encryption in link relayer
+    LINK_KEY = bytes.fromhex('287ad379dca402530a39f1f43047b835')
+    two_devices.devices[0].on_link_key(
+        two_devices.devices[1].public_address,
+        LINK_KEY,
+        HCI_AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P_256_TYPE,
+    )
+    two_devices.devices[1].on_link_key(
+        two_devices.devices[0].public_address,
+        LINK_KEY,
+        HCI_AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P_256_TYPE,
+    )
+    two_devices.connections[0].encryption = 1
+    two_devices.connections[1].encryption = 1
+
+    paired = [
+        asyncio.get_event_loop().create_future(),
+        asyncio.get_event_loop().create_future(),
+    ]
+
+    def on_pairing(which: int, keys: PairingKeys):
+        paired[which].set_result(keys)
+
+    two_devices.connections[0].on('pairing', lambda keys: on_pairing(0, keys))
+    two_devices.connections[1].on('pairing', lambda keys: on_pairing(1, keys))
+
+    # Mock SMP
+    with patch('bumble.smp.Session', spec=True) as MockSmpSession:
+        MockSmpSession.send_pairing_confirm_command = MagicMock()
+        MockSmpSession.send_pairing_dhkey_check_command = MagicMock()
+        MockSmpSession.send_public_key_command = MagicMock()
+        MockSmpSession.send_pairing_random_command = MagicMock()
+
+        # Start CTKD
+        await two_devices.connections[0].pair()
+        await asyncio.gather(*paired)
+
+        # Phase 2 commands should not be invoked
+        MockSmpSession.send_pairing_confirm_command.assert_not_called()
+        MockSmpSession.send_pairing_dhkey_check_command.assert_not_called()
+        MockSmpSession.send_public_key_command.assert_not_called()
+        MockSmpSession.send_pairing_random_command.assert_not_called()
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_self_smp_public_address():
+    pairing_config = PairingConfig(
+        mitm=True,
+        sc=True,
+        bonding=True,
+        identity_address_type=PairingConfig.AddressType.PUBLIC,
+        delegate=PairingDelegate(
+            PairingDelegate.IoCapability.DISPLAY_OUTPUT_AND_YES_NO_INPUT,
+            PairingDelegate.KeyDistribution.DISTRIBUTE_ENCRYPTION_KEY
+            | PairingDelegate.KeyDistribution.DISTRIBUTE_IDENTITY_KEY
+            | PairingDelegate.KeyDistribution.DISTRIBUTE_SIGNING_KEY
+            | PairingDelegate.KeyDistribution.DISTRIBUTE_LINK_KEY,
+        ),
+    )
+
+    await _test_self_smp_with_configs(pairing_config, pairing_config)
+
+
+# -----------------------------------------------------------------------------
 async def run_test_self():
     await test_self_connection()
     await test_self_gatt()
@@ -481,6 +584,8 @@
     await test_self_smp()
     await test_self_smp_reject()
     await test_self_smp_wrong_pin()
+    await test_self_smp_over_classic()
+    await test_self_smp_public_address()
 
 
 # -----------------------------------------------------------------------------
diff --git a/tools/__init__.py b/tools/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tools/__init__.py
diff --git a/utils/generate_company_id_list.py b/tools/generate_company_id_list.py
similarity index 100%
rename from utils/generate_company_id_list.py
rename to tools/generate_company_id_list.py
diff --git a/tools/rtk_fw_download.py b/tools/rtk_fw_download.py
new file mode 100644
index 0000000..b027141
--- /dev/null
+++ b/tools/rtk_fw_download.py
@@ -0,0 +1,149 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+import logging
+import pathlib
+import urllib.request
+import urllib.error
+
+import click
+
+from bumble.colors import color
+from bumble.drivers import rtk
+from bumble.tools import rtk_util
+
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+
+# -----------------------------------------------------------------------------
+# Constants
+# -----------------------------------------------------------------------------
+LINUX_KERNEL_GIT_SOURCE = (
+    "https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/plain/rtl_bt",
+    False,
+)
+REALTEK_OPENSOURCE_SOURCE = (
+    "https://github.com/Realtek-OpenSource/android_hardware_realtek/raw/rtk1395/bt/rtkbt/Firmware/BT",
+    True,
+)
+LINUX_FROM_SCRATCH_SOURCE = (
+    "https://anduin.linuxfromscratch.org/sources/linux-firmware/rtl_bt",
+    False,
+)
+
+# -----------------------------------------------------------------------------
+# Functions
+# -----------------------------------------------------------------------------
+def download_file(base_url, name, remove_suffix):
+    if remove_suffix:
+        name = name.replace(".bin", "")
+
+    url = f"{base_url}/{name}"
+    with urllib.request.urlopen(url) as file:
+        data = file.read()
+        print(f"Downloaded {name}: {len(data)} bytes")
+        return data
+
+
+# -----------------------------------------------------------------------------
+@click.command
+@click.option(
+    "--output-dir",
+    default=".",
+    help="Output directory where the files will be saved",
+    show_default=True,
+)
+@click.option(
+    "--source",
+    type=click.Choice(["linux-kernel", "realtek-opensource", "linux-from-scratch"]),
+    default="linux-kernel",
+    show_default=True,
+)
+@click.option("--single", help="Only download a single image set, by its base name")
+@click.option("--force", is_flag=True, help="Overwrite files if they already exist")
+@click.option("--parse", is_flag=True, help="Parse the FW image after saving")
+def main(output_dir, source, single, force, parse):
+    """Download RTK firmware images and configs."""
+
+    # Check that the output dir exists
+    output_dir = pathlib.Path(output_dir)
+    if not output_dir.is_dir():
+        print("Output dir does not exist or is not a directory")
+        return
+
+    base_url, remove_suffix = {
+        "linux-kernel": LINUX_KERNEL_GIT_SOURCE,
+        "realtek-opensource": REALTEK_OPENSOURCE_SOURCE,
+        "linux-from-scratch": LINUX_FROM_SCRATCH_SOURCE,
+    }[source]
+
+    print("Downloading")
+    print(color("FROM:", "green"), base_url)
+    print(color("TO:", "green"), output_dir)
+
+    if single:
+        images = [(f"{single}_fw.bin", f"{single}_config.bin", True)]
+    else:
+        images = [
+            (driver_info.fw_name, driver_info.config_name, driver_info.config_needed)
+            for driver_info in rtk.Driver.DRIVER_INFOS
+        ]
+
+    for (fw_name, config_name, config_needed) in images:
+        print(color("---", "yellow"))
+        fw_image_out = output_dir / fw_name
+        if not force and fw_image_out.exists():
+            print(color(f"{fw_image_out} already exists, skipping", "red"))
+            continue
+        if config_name:
+            config_image_out = output_dir / config_name
+            if not force and config_image_out.exists():
+                print(color("f{config_out} already exists, skipping", "red"))
+                continue
+
+        try:
+            fw_image = download_file(base_url, fw_name, remove_suffix)
+        except urllib.error.HTTPError as error:
+            print(f"Failed to download {fw_name}: {error}")
+            continue
+
+        config_image = None
+        if config_name:
+            try:
+                config_image = download_file(base_url, config_name, remove_suffix)
+            except urllib.error.HTTPError as error:
+                if config_needed:
+                    print(f"Failed to download {config_name}: {error}")
+                    continue
+                else:
+                    print(f"No config available as {config_name}")
+
+        fw_image_out.write_bytes(fw_image)
+        if parse and config_name:
+            print(color("Parsing:", "cyan"), fw_name)
+            rtk_util.do_parse(fw_image_out)
+        if config_image:
+            config_image_out.write_bytes(config_image)
+
+
+# -----------------------------------------------------------------------------
+if __name__ == '__main__':
+    main()
diff --git a/tools/rtk_util.py b/tools/rtk_util.py
new file mode 100644
index 0000000..7452915
--- /dev/null
+++ b/tools/rtk_util.py
@@ -0,0 +1,161 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+import logging
+import asyncio
+import os
+
+import click
+
+from bumble import transport
+from bumble.host import Host
+from bumble.drivers import rtk
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+
+# -----------------------------------------------------------------------------
+def do_parse(firmware_path):
+    with open(firmware_path, 'rb') as firmware_file:
+        firmware_data = firmware_file.read()
+        firmware = rtk.Firmware(firmware_data)
+        print(
+            f"Firmware: version=0x{firmware.version:08X} "
+            f"project_id=0x{firmware.project_id:04X}"
+        )
+        for patch in firmware.patches:
+            print(
+                f"  Patch: chip_id=0x{patch[0]:04X}, "
+                f"{len(patch[1])} bytes, "
+                f"SVN Version={patch[2]:08X}"
+            )
+
+
+# -----------------------------------------------------------------------------
+async def do_load(usb_transport, force):
+    async with await transport.open_transport_or_link(usb_transport) as (
+        hci_source,
+        hci_sink,
+    ):
+        # Create a host to communicate with the device
+        host = Host(hci_source, hci_sink)
+        await host.reset(driver_factory=None)
+
+        # Get the driver.
+        driver = await rtk.Driver.for_host(host, force)
+        if driver is None:
+            if not force:
+                print("Firmware already loaded or no supported driver for this device.")
+                return
+
+        await driver.download_firmware()
+
+
+# -----------------------------------------------------------------------------
+async def do_drop(usb_transport):
+    async with await transport.open_transport_or_link(usb_transport) as (
+        hci_source,
+        hci_sink,
+    ):
+        # Create a host to communicate with the device
+        host = Host(hci_source, hci_sink)
+        await host.reset(driver_factory=None)
+
+        # Tell the device to reset/drop any loaded patch
+        await rtk.Driver.drop_firmware(host)
+
+
+# -----------------------------------------------------------------------------
+async def do_info(usb_transport, force):
+    async with await transport.open_transport(usb_transport) as (
+        hci_source,
+        hci_sink,
+    ):
+        # Create a host to communicate with the device
+        host = Host(hci_source, hci_sink)
+        await host.reset(driver_factory=None)
+
+        # Check if this is a supported device.
+        if not force and not rtk.Driver.check(host):
+            print("USB device not supported by this RTK driver")
+            return
+
+        # Get the driver info.
+        driver_info = await rtk.Driver.driver_info_for_host(host)
+        if driver_info:
+            print(
+                "Driver:\n"
+                f"  ROM:      {driver_info.rom:04X}\n"
+                f"  Firmware: {driver_info.fw_name}\n"
+                f"  Config:   {driver_info.config_name}\n"
+            )
+        else:
+            print("Firmware already loaded or no supported driver for this device.")
+
+
+# -----------------------------------------------------------------------------
+@click.group()
+def main():
+    logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'INFO').upper())
+
+
+@main.command
+@click.argument("firmware_path")
+def parse(firmware_path):
+    """Parse a firmware image."""
+    do_parse(firmware_path)
+
+
+@main.command
+@click.argument("usb_transport")
+@click.option(
+    "--force",
+    is_flag=True,
+    default=False,
+    help="Load even if the USB info doesn't match",
+)
+def load(usb_transport, force):
+    """Load a firmware image into the USB dongle."""
+    asyncio.run(do_load(usb_transport, force))
+
+
+@main.command
+@click.argument("usb_transport")
+def drop(usb_transport):
+    """Drop a firmware image from the USB dongle."""
+    asyncio.run(do_drop(usb_transport))
+
+
+@main.command
+@click.argument("usb_transport")
+@click.option(
+    "--force",
+    is_flag=True,
+    default=False,
+    help="Try to get the device info even if the USB info doesn't match",
+)
+def info(usb_transport, force):
+    """Get the firmware info from a USB dongle."""
+    asyncio.run(do_info(usb_transport, force))
+
+
+# -----------------------------------------------------------------------------
+if __name__ == '__main__':
+    main()