en/devices/accessories/headset/usb-headset-spec.html - platform/docs/source.android.com - Git at Google

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     <title>USB Headset: Accessory Specification</title>
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 <p>
 This documentation specifies some characteristics of USB headsets, so that
 they function uniformly across the Android ecosystem. Only headsets with
 digital USB audio interface are permitted. Purely analog headsets with
 mechanical adaptation to USB-C are not permitted, as per USB Type-C
 specification.
 </p>
 <p>
 This documentation specifies the minimum requirements: accessory manufacturers
 are encouraged to add features while keeping these requirements in mind.
 </p>

 <h2 id="functional-overview">Functional overview</h2>
 <p>
 USB headsets can implement a variety of basic and advanced features. This
 specification only covers mandated basic features:
 </p>
 <ul>
  <li>Stereo output</li>
  <li>Optional, but recommended, microphone</li>
  <li>Function buttons for volume, playback, and call control</li>
 </ul>

 <h2 id="terminal-types">USB Audio Class terminal types</h2>
 <p>
 Headphones and headsets must report these USB Audio Class (UAC) terminal types:
 </p>

 <ul>
  <li><strong>Headphones</strong>. Low impedance transducers, &lt; 100 ohms, no
  microphone: 0x0302</li>
  <li><strong>Headset</strong>. Low impedance transducers with microphone: 0x0402</li>
 </ul>

 <h2 id="control-function">Control functions</h2>
 <p>Headsets can come with varying number of buttons to control specific
 functions, such as volume and play/pause.<p>
 <table>
   <tr>
    <th>Control function</th>
    <th>Accessory Support</th>
    <th>Description</th>
   </tr>
   <tr>
    <td>A</td>
    <td>Required</td>
    <td>Play/pause (short press), launch voice command (long press), next (double
        press)</td>
   </tr>
   <tr>
    <td>B</td>
    <td>Optional</td>
    <td>Vol+</td>
   </tr>
   <tr>
    <td>C</td>
    <td>Optional</td>
    <td>Vol-</td>
   </tr>
   <tr>
    <td>D</td>
    <td>Optional</td>
    <td>Launch voice command</td>
   </tr>
 </table>
 <p>
 <strong>Assign functions to buttons as follows:</strong>
 </p>
 <ul>
   <li>All one-button headsets must implement Function A.</li>
   <li>Headsets with multiple buttons must implement functions according to the
       following pattern:
     <ul>
       <li>2 functions: A and D</li>
       <li>3 functions: A, B, C</li>
       <li>4 functions: A, B, C, D</li>
     </ul>
   </li>
 </ul>
 <p class="note">
 <strong>Note</strong>: No key latching allowed. Each key press by the end user
 must generate the corresponding "down" and "up" key event, matching the end user
 action. In other words, the keys for functions A through D are never "latched"
 or implemented to be used as a toggle (where the "up" event only follows "down"
 on a second key press).
 </p>
 <h2 id="software-mapping">Software mapping</h2>
 <p>
 Compatible USB headsets are required to support the following software mappings
 for the headset buttons. Devices match these HID mappings with the appropriate
 Android keycode.
 </p>

 <table>
   <tr>
    <th>Function</th>
    <th>Mappings</th>
   </tr>
   <tr>
    <td>A</td>
    <td>HID usage page: 0x0C<br>
        HID usage: 0x0CD </td>
   </tr>
   <tr>
    <td>B </td>
    <td>HID usage page: 0x0C<br>
        HID usage: 0x0E9</td>
   </tr>
   <tr>
    <td>C</td>
    <td>HID usage page: 0x0C<br>
        HID usage: 0x0EA</td>
   </tr>
   <tr>
    <td>D </td>
    <td>HID usage page: 0x0C<br>
        HID usage: 0x0CF</td>
   </tr>
 </table>

 <p class="note">Key mappings should be declared within a HID application
 collection. For accessories without a microphone, use Headphone (Usage
 Page: Consumer (0x0C), Usage: Headphone (0x05)). For accesories with a
 microphone, use Headset (Usage Page: Telephony (0x0B), Usage: Headset (0x05)).</p>

 <h2 id="output-level">Output level</h2>
 <p>
 The maximum sound pressure level shall comply to any regulatory requirement in
 the country of destination.
 </p>

 <h2 id="mechanical">Mechanical</h2>
 <p>
 Accessory manufacturers must follow the requirements for USB connectors
 as specified by <a href="http://www.usb.org/">USB.org</a>.
 </p>

   </body>
 </html>
	<html devsite>
	<head>
	<title>USB Headset: Accessory Specification</title>
	<meta name="project_path" value="/_project.yaml" />
	<meta name="book_path" value="/_book.yaml" />
	</head>
	<body>
	<!--
	Copyright 2017 The Android Open Source Project

	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.
	-->



	<p>
	This documentation specifies some characteristics of USB headsets, so that
	they function uniformly across the Android ecosystem. Only headsets with
	digital USB audio interface are permitted. Purely analog headsets with
	mechanical adaptation to USB-C are not permitted, as per USB Type-C
	specification.
	</p>
	<p>
	This documentation specifies the minimum requirements: accessory manufacturers
	are encouraged to add features while keeping these requirements in mind.
	</p>

	<h2 id="functional-overview">Functional overview</h2>
	<p>
	USB headsets can implement a variety of basic and advanced features. This
	specification only covers mandated basic features:
	</p>
	<ul>
	<li>Stereo output</li>
	<li>Optional, but recommended, microphone</li>
	<li>Function buttons for volume, playback, and call control</li>
	</ul>

	<h2 id="terminal-types">USB Audio Class terminal types</h2>
	<p>
	Headphones and headsets must report these USB Audio Class (UAC) terminal types:
	</p>

	<ul>
	<li><strong>Headphones</strong>. Low impedance transducers, < 100 ohms, no
	microphone: 0x0302</li>
	<li><strong>Headset</strong>. Low impedance transducers with microphone: 0x0402</li>
	</ul>

	<h2 id="control-function">Control functions</h2>
	<p>Headsets can come with varying number of buttons to control specific
	functions, such as volume and play/pause.<p>
	<table>
	<tr>
	<th>Control function</th>
	<th>Accessory Support</th>
	<th>Description</th>
	</tr>
	<tr>
	<td>A</td>
	<td>Required</td>
	<td>Play/pause (short press), launch voice command (long press), next (double
	press)</td>
	</tr>
	<tr>
	<td>B</td>
	<td>Optional</td>
	<td>Vol+</td>
	</tr>
	<tr>
	<td>C</td>
	<td>Optional</td>
	<td>Vol-</td>
	</tr>
	<tr>
	<td>D</td>
	<td>Optional</td>
	<td>Launch voice command</td>
	</tr>
	</table>
	<p>
	<strong>Assign functions to buttons as follows:</strong>
	</p>
	<ul>
	<li>All one-button headsets must implement Function A.</li>
	<li>Headsets with multiple buttons must implement functions according to the
	following pattern:
	<ul>
	<li>2 functions: A and D</li>
	<li>3 functions: A, B, C</li>
	<li>4 functions: A, B, C, D</li>
	</ul>
	</li>
	</ul>
	<p class="note">
	<strong>Note</strong>: No key latching allowed. Each key press by the end user
	must generate the corresponding "down" and "up" key event, matching the end user
	action. In other words, the keys for functions A through D are never "latched"
	or implemented to be used as a toggle (where the "up" event only follows "down"
	on a second key press).
	</p>
	<h2 id="software-mapping">Software mapping</h2>
	<p>
	Compatible USB headsets are required to support the following software mappings
	for the headset buttons. Devices match these HID mappings with the appropriate
	Android keycode.
	</p>

	<table>
	<tr>
	<th>Function</th>
	<th>Mappings</th>
	</tr>
	<tr>
	<td>A</td>
	<td>HID usage page: 0x0C<br>
	HID usage: 0x0CD </td>
	</tr>
	<tr>
	<td>B </td>
	<td>HID usage page: 0x0C<br>
	HID usage: 0x0E9</td>
	</tr>
	<tr>
	<td>C</td>
	<td>HID usage page: 0x0C<br>
	HID usage: 0x0EA</td>
	</tr>
	<tr>
	<td>D </td>
	<td>HID usage page: 0x0C<br>
	HID usage: 0x0CF</td>
	</tr>
	</table>

	<p class="note">Key mappings should be declared within a HID application
	collection. For accessories without a microphone, use Headphone (Usage
	Page: Consumer (0x0C), Usage: Headphone (0x05)). For accesories with a
	microphone, use Headset (Usage Page: Telephony (0x0B), Usage: Headset (0x05)).</p>

	<h2 id="output-level">Output level</h2>
	<p>
	The maximum sound pressure level shall comply to any regulatory requirement in
	the country of destination.
	</p>

	<h2 id="mechanical">Mechanical</h2>
	<p>
	Accessory manufacturers must follow the requirements for USB connectors
	as specified by <a href="http://www.usb.org/">USB.org</a>.
	</p>

	</body>
	</html>