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   <p>Several <a href="/compatibility/cts/">Android Compatibility Test Suite
   (CTS)</a> tests for <a href="/devices/audio/usb">Android USB audio</a>
   require the physical connection of USB audio
   peripherals. For these, additional CTS Verifier tests have been implemented.</p>


   <h2 id="nomenclature">Nomenclature</h2>


   <p>Throughout this document, the term "device" and "peripheral" are used in a
   very precise manner:</p>


   <ul>
     <li><em>Device</em> refers to the Android device.</li>


     <li><em>Peripheral</em> refers to an external USB audio peripheral
     connected to the Android device.</li>
   </ul>


   <h2 id="recommended-peripherals">Mandated peripherals</h2>


   <p>For the USB audio CTS Verifier Tests to know the attributes and
   capabilities they are verifying, it is necessary to specify a set of known
   peripherals to test against. For this reason, specific brands and types are
   mandated below. Some tests require a specifically mandated peripheral. Other
   tests simply require a USB audio peripheral that meets the requirements of
   those specific test. Note that any of the peripherals mandated for the USB
   Audio Peripherals Attributes Test will be compatible with the requirements
   for the Play and Record tests.</p>


   <h3 id="usb-audio-interface">USB audio interface</h3>


   <p>Use one of the peripherals here to conduct the USB Audio Peripheral
   Attributes test. They can also be used for the Play test and Record test.</p>


   <ul>
     <li><a href="http://www.presonus.com/products/audiobox-22VSL" class="external">Presonus
     AudioBox 22VSL</a>
     </li>


     <li><a href="https://www.presonus.com/products/audiobox-usb" class="external">Presonus
     AudioBox USB</a>
     </li>
   </ul>


   <p>Note that these two peripherals have been discontinued by the manufacturer
   and will be deprecated in a future CTS Verifier release.</p>


   <ul>
     <li><a href=
     "https://focusrite.com/usb-audio-interface/scarlett/scarlett-2i4" class="external">
     Focusrite Scarlett 2i4</a>
     </li>


     <li><a href=
     "http://www.musictribe.com/Categories/Behringer/Computer-Audio/Interfaces/UMC204HD/p/P0BK0" class="external">
     Behringer UMC204HD</a>
     </li>


     <li><a href=
     "https://www.roland.com/us/products/rubix24/" class="external">
     Roland Rubix 24</a>
     </li>


     <li><a href=
     "https://www.presonus.com/products/AudioBox-USB-96" class="external">
     PreSonus AudioBox 96</a>
     </li>
   </ul>


   <table>
     <tr>
       <td width="50%">A USB audio interface (A PreSonus AudioBox 22VSL).</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/usb_audio_interface.png" alt=
       "USB audio interface" width="300" id="usb_audio_interface">
       </td>
     </tr>
   </table>


   <h3 id="usb-headset">USB headset</h3>


   <p>The CTS Verifier USB Audio Buttons Test does not require a specific USB
   headset peripheral. It can be an instance of either of the following:</p>


   <ul>
     <li><span style="color:#202124;">A USB Headset peripheral that supports the
     <a href=
     "/devices/accessories/headset/usb-headset-spec">Android
     USB Headset Accessory Specification</a><span style="color:#202124;">. These
     headset peripherals are often indicated by the manufacturer as "Made for
     Android".</span></span>
     </li>


     <li>An analog headset which supports the
     <a href=
     "/devices/accessories/headset/usb-headset-spec">Android
     USB Headset Accessory Specification </a>connected to a USB to analog audio converter (such as the
     <a href=
     "https://store.google.com/us/product/usb_c_headphone_adapter" class="external">Google USB-C
     digital to 3.5 mm headphone adapter</a> or <a href=
     "https://www.htc.com/us/accessories-b/#!pid=htc-u11&amp;acc=usb-c-digital-to-3-5mm-htc-u11"
     class="external">HTC USB-C digital to 3.5mm audio jack adapter</a>).
     <p>Known examples of compatible analog headset peripherals include the
     <a href="https://www.bose.com/en_us/products/headphones/earphones/soundsport-in-ear-headphones-samsung-devices.html"
     class="external">
     Bose SoundSport® in-ear headphones – Samsung and Android™ devices</a>, and
     the <a href=
     "https://www.urbanears.com/ue_us_en/reimers#reimers-black-belt" class="external" >UrbanEars
     Reimers Black Belt made for Android</a> headsets. These analog headsets
     must be connected to the device USB port via a USB to Audio
       converter.</p>
     </li>
   </ul>


   <p>Note that in either case, the button must produce virtual key codes for all three of the
   required buttons (volume up, volume down, play/pause) for the test to succeed.
   Refer to the Software mapping section in <a href="/devices/accessories/headset/usb-headset-spec">
   Android USB Headset Accessory Specification</a> for the virtual key codes.</p>


   <table>
     <tr>
       <td width="50%">A USB headset.</td>

       <td width="50%"><img src="/compatibility/cts/images/usb_headset.png" alt=
       "USB headset" width="300" id="usb_headset">
       </td>
     </tr>
   </table>


   <h2 id="required-additional-hardware">Required additional hardware</h2>


   <p>Patch cables (for loopback) 2 short ¼" male to ¼" male patch cables to
   connect the outputs to the inputs of the USB</p>


   <table>
     <tr>
       <td width="50%">¼" male to ¼" male patch cables.</td>

       <td width="50%"><img src="/compatibility/cts/images/patch_cables.png"
       alt="patch cables" width="300" id="patch_cables">
       </td>
     </tr>
   </table>


   <p>USB peripheral cable</p>


   <table>
     <tr>
       <td width="50%">This cable (which typically comes with the peripheral),
       connects the USB audio peripheral to the host device.</td>

       <td width="50%"><img src="/compatibility/cts/images/peripheral_cable.png"
       alt="peripheral cable" width="300" id="peripheral_cable">
       </td>
     </tr>
   </table>


   <p>USB "On The Go" (OTG) adapter</p>


   <table>
     <tr>
       <td width="50%">A USB "On The Go" (OTG) adapter is required to physically
       connect the peripheral to the Android device and indicate to the Android
       device that it should assume the role of "host".</td>

       <td width="50%"><img src="/compatibility/cts/images/otg_adapter.png" alt=
       "OTG adapter" width="300" id="otg_adapter">
       </td>
     </tr>
   </table>


   <p>Analog headphones to monitor the output of the USB audio interface for the
   Play test.</p>


   <table>
     <tr>
       <td width="50%">Set of analog headphones.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/analog_headphones.png" alt="analog headphones"
       width="300" id="analog_headphones">
       </td>
     </tr>
   </table>


   <h2 id="tests">Tests</h2>


   <p>In each test, indicate test success by clicking the <strong>test
   pass</strong> (check mark) button. Otherwise, indicate test failure by
   clicking the <strong>test fail</strong> (exclamation point) button.</p>


   <h3 id="attributes-test">Attributes test</h3>


   <h4 id="abstract">Abstract</h4>


   <p>This test verifies that the attributes (supported sample-rates, channel
   configurations, sample formats, etc.) match the set of a-priori known attributes
   of the device.</p>


   <h4 id="process">Process</h4>


   <p>After invoking the test from the main menu, connect a USB audio
   peripheral. If the attributes match, the <strong>test pass</strong> (check
   mark) button will be enabled.</p>


   <table>
     <tr>
       <td width="50%">Select <em>USB Audio Peripheral Attributes
       Test.</em></td>

       <td width="50%"><img src="/compatibility/cts/images/attributes_test.png"
       alt="attributes test" width="300" id="attributes test">
       </td>
     </tr>


     <tr>
       <td width="50%">Summary of instructions is displayed.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/attributes_summary.png" alt=
       "attributes summary" width="300" id="attributes_summary">
       </td>
     </tr>


     <tr>
       <td width="50%">Pre-connect screen.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/attributes_preconnect.png" alt=
       "attributes preconnect" width="300" id="attributes_preconnect">
       </td>
     </tr>


     <tr>
       <td width="50%">USB audio peripheral connected to Android Device with
       peripheral cable and OTG adapter.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/attributes_connected.png" alt=
       "attributes connected" width="300" id="attributes_connected">
       </td>
     </tr>


     <tr>
       <td width="50%">Post-connect screen.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/attributes_postconnect.png" alt=
       "attributes post connection" width="300" id="attributes_postconnect">
       </td>
     </tr>
   </table>


   <h3 id="play-test">Play test</h3>


   <h4 id="abstract">Abstract</h4>


   <p>This test verifies that audio playback is functioning. It does this by
   generating a 1KHz test tone and presenting it in stereo (two-channels) to the
   USB audio peripheral.</p>


   <h4 id="process">Process</h4>


   <p>After invoking the test from the main menu, connect the USB audio
   interface, including the analog headset, to the headset output jack on the
   interface for monitoring.</p>


   <p>Press the <strong>PLAY</strong> button. If the test tone is heard in both
   channels of the headset, indicate test pass by clicking the <strong>test
   pass</strong> (check mark) button. If either or both of the channels do not
   play the tone, indicate test failure by clicking the <strong>test
   fail</strong> (exclamation point) button.</p>


   <h4 id="notes">Notes</h4>


   <table>
     <tr>
       <td width="50%">Select <em>USB Audio Peripheral Play Test.</em></td>

       <td width="50%"><img src="/compatibility/cts/images/play_test.png" alt=
       "play test" width="300" id="play_test">
       </td>
     </tr>


     <tr>
       <td width="50%">Summary of instructions is displayed.</td>

       <td width="50%"><img src="/compatibility/cts/images/play_summary.png"
       alt="play summary" width="300" id="play_summary">
       </td>
     </tr>


     <tr>
       <td width="50%">Pre-connect screen.</td>

       <td width="50%"><img src="/compatibility/cts/images/play_preconnect.png"
       alt="play preconnect" width="300" id="play_preconnect">
       </td>
     </tr>


     <tr>
       <td width="50%">
         Connect the USB audio peripheral to the Android Device.

         <p>The headphones are connected to the headphone output jack on the USB
         audio interface for monitoring.</p>
       </td>

       <td width="50%"><img src="/compatibility/cts/images/play_connected.png"
       alt="play connected" width="300" id="play_connected">
       </td>
     </tr>


     <tr>
       <td width="50%">Post-connect screen.</td>

       <td width="50%"><img src="/compatibility/cts/images/play_postconnect.png"
       alt="play post connection" width="300" id="play_postconnect">
       </td>
     </tr>
   </table>


   <h3 id="record-loopback-test">Record (loopback) test</h3>


   <h4 id="abstract">Abstract</h4>


   <p>This test verifies that audio recording is functioning. It does this by
   generating a tone at the outputs of the USB audio interface, which is then
   routed via patch cords to the inputs of the USB audio peripheral.</p>


   <h4 id="process">Process</h4>


   <p>After invoking the test from the main menu, connect the USB audio
   interface. Connect the analog outputs to the analog inputs with patch cables.
   Press the <strong>RECORD LOOPBACK</strong> button. If both the channels of
   the recorded test tone are shown in the view below, indicate test pass by
   clicking the <strong>test pass</strong> (check mark) button. If either or
   both of the channels does not display, indicate test failure by clicking the
   <strong>test fail</strong> (exclamation point) button.</p>


   <h4 id="notes">Notes</h4>


   <p>Ensure positive connection of both input and output jacks on the
   peripheral. It will be necessary to adjust the input levels to correctly
   display the recorded signal.</p>


   <table>
     <tr>
       <td width="50%">Select <em>USB Audio Peripheral Record Test.</em></td>

       <td width="50%"><img src="/compatibility/cts/images/record_test.png" alt=
       "record test" width="300" id="record_test">
       </td>
     </tr>


     <tr>
       <td width="50%">Summary of instructions is displayed.</td>

       <td width="50%"><img src="/compatibility/cts/images/record_summary.png"
       alt="record summary" width="300" id="record_summary">
       </td>
     </tr>


     <tr>
       <td width="50%">Pre-connect screen.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/record_preconnect.png" alt="record preconnect"
       width="300" id="record_preconnect">
       </td>
     </tr>


     <tr>
       <td width="50%">USB audio Interface with loopback connected to Android
       device.</td>

       <td width="50%"><img src="/compatibility/cts/images/record_connected.png"
       alt="record connected" width="300" id="record_connected">
       </td>
     </tr>


     <tr>
       <td width="50%">Connections on the back of the USB audio interface.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/record_connected_back.png" alt=
       "record connected in back" width="300" id="record_connected_back">
       </td>
     </tr>


     <tr>
       <td width="50%">Connections on the front of the USB audio interface.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/record_connected_front.png" alt=
       "record connected in front" width="300" id="record_connected_front">
       </td>
     </tr>


     <tr>
       <td width="50%">Post-connect screen.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/record_postconnect.png" alt=
       "record post connection" width="300" id="record_postconnect">
       </td>
     </tr>
   <tr>
       <td width="50%">Post-connect screen, with record test running.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/record_postconnect_running.png" alt=
       "record postconnect running" width="300" id="attributes_postconnect_running.">
       </td>
     </tr>
   </table>


   <h3 id="headset-buttons-test">Headset buttons test</h3>


   <h4 id="abstract">Abstract</h4>


   <p>This test verifies the <strong>media/transport</strong> buttons on the
   recommended headset are correctly recognized.</p>


   <h4 id="process">Process</h4>


   <p>After invoking the test from the main menu, connect the USB headset
   peripheral. Press each <strong>media/transport</strong> (play, pause, volume
   up & volume down) button on the headset. As each is recognized, it will be
   recognized in the test panel. When all buttons have been recognized, the
   <strong>test pass</strong> (check mark) button will be enabled. Click the
   <strong>test pass</strong> button to indicate success. If the full set of
   buttons is not recognized, indicate test failure by clicking the <strong>test
   fail</strong> (exclamation point) button.</p>


   <h4 id="notes">Notes</h4>


   <table>
     <tr>
       <td width="50%">
         The USB headset peripheral connected to the Android device.

         <p>Note the OTG adapter.</p>
       </td>

       <td width="50%"><img src=
       "/compatibility/cts/images/buttons_connected.png" alt="buttons connected"
       width="300" id="buttons_connected">
       </td>
     </tr>


     <tr>
       <td width="50%">Select <em>USB Audio Peripheral Buttons Test.</em></td>

       <td width="50%"><img src="/compatibility/cts/images/buttons_test.png"
       alt="buttons test" width="300" id="buttons_test">
       </td>
     </tr>


     <tr>
       <td width="50%">Summary of instructions is displayed.</td>

       <td width="50%"><img src="/compatibility/cts/images/buttons_summary.png"
       alt="buttons summary" width="300" id="buttons_summary">
       </td>
     </tr>


     <tr>
       <td width="50%">
         Peripheral connected, but no buttons recognized (yet).

         <p>Note that the expected (buttons which are known to the device
         profile) are indicated with  white text; those that are not part of
         the test peripheral are displayed in grey text.</p>
       </td>

       <td width="50%"><img src=
       "/compatibility/cts/images/buttons_not_recognized.png" alt=
       "buttons not recognized" width="300" id="buttons not recognized">
       </td>
     </tr>


     <tr>
       <td width="50%">Peripheral connected, and expected buttons
       recognized.</td>

       <td width="50%"><img src=
       "/compatibility/cts/images/buttons_recognized.png" alt=
       "buttons recognized" width="300" id="buttons recognized">
       </td>
     </tr>
   </table>
 </body>
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	<head>
	<title>USB Audio CTS Verifier Tests</title>
	<meta name="project_path" value="/_project.yaml" />
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	Copyright 2017 The Android Open Source Project

	Licensed under the Apache License, Version 2.0 (the "License");
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	<p>Several <a href="/compatibility/cts/">Android Compatibility Test Suite
	(CTS)</a> tests for <a href="/devices/audio/usb">Android USB audio</a>
	require the physical connection of USB audio
	peripherals. For these, additional CTS Verifier tests have been implemented.</p>


	<h2 id="nomenclature">Nomenclature</h2>


	<p>Throughout this document, the term "device" and "peripheral" are used in a
	very precise manner:</p>


	<ul>
	<li><em>Device</em> refers to the Android device.</li>


	<li><em>Peripheral</em> refers to an external USB audio peripheral
	connected to the Android device.</li>
	</ul>


	<h2 id="recommended-peripherals">Mandated peripherals</h2>


	<p>For the USB audio CTS Verifier Tests to know the attributes and
	capabilities they are verifying, it is necessary to specify a set of known
	peripherals to test against. For this reason, specific brands and types are
	mandated below. Some tests require a specifically mandated peripheral. Other
	tests simply require a USB audio peripheral that meets the requirements of
	those specific test. Note that any of the peripherals mandated for the USB
	Audio Peripherals Attributes Test will be compatible with the requirements
	for the Play and Record tests.</p>


	<h3 id="usb-audio-interface">USB audio interface</h3>


	<p>Use one of the peripherals here to conduct the USB Audio Peripheral
	Attributes test. They can also be used for the Play test and Record test.</p>


	<ul>
	<li><a href="http://www.presonus.com/products/audiobox-22VSL" class="external">Presonus
	AudioBox 22VSL</a>
	</li>


	<li><a href="https://www.presonus.com/products/audiobox-usb" class="external">Presonus
	AudioBox USB</a>
	</li>
	</ul>


	<p>Note that these two peripherals have been discontinued by the manufacturer
	and will be deprecated in a future CTS Verifier release.</p>


	<ul>
	<li><a href=
	"https://focusrite.com/usb-audio-interface/scarlett/scarlett-2i4" class="external">
	Focusrite Scarlett 2i4</a>
	</li>


	<li><a href=
	"http://www.musictribe.com/Categories/Behringer/Computer-Audio/Interfaces/UMC204HD/p/P0BK0" class="external">
	Behringer UMC204HD</a>
	</li>


	<li><a href=
	"https://www.roland.com/us/products/rubix24/" class="external">
	Roland Rubix 24</a>
	</li>


	<li><a href=
	"https://www.presonus.com/products/AudioBox-USB-96" class="external">
	PreSonus AudioBox 96</a>
	</li>
	</ul>


	<table>
	<tr>
	<td width="50%">A USB audio interface (A PreSonus AudioBox 22VSL).</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/usb_audio_interface.png" alt=
	"USB audio interface" width="300" id="usb_audio_interface">
	</td>
	</tr>
	</table>


	<h3 id="usb-headset">USB headset</h3>


	<p>The CTS Verifier USB Audio Buttons Test does not require a specific USB
	headset peripheral. It can be an instance of either of the following:</p>


	<ul>
	<li><span style="color:#202124;">A USB Headset peripheral that supports the
	<a href=
	"/devices/accessories/headset/usb-headset-spec">Android
	USB Headset Accessory Specification</a><span style="color:#202124;">. These
	headset peripherals are often indicated by the manufacturer as "Made for
	Android".</span></span>
	</li>


	<li>An analog headset which supports the
	<a href=
	"/devices/accessories/headset/usb-headset-spec">Android
	USB Headset Accessory Specification </a>connected to a USB to analog audio converter (such as the
	<a href=
	"https://store.google.com/us/product/usb_c_headphone_adapter" class="external">Google USB-C
	digital to 3.5 mm headphone adapter</a> or <a href=
	"https://www.htc.com/us/accessories-b/#!pid=htc-u11&acc=usb-c-digital-to-3-5mm-htc-u11"
	class="external">HTC USB-C digital to 3.5mm audio jack adapter</a>).
	<p>Known examples of compatible analog headset peripherals include the
	<a href="https://www.bose.com/en_us/products/headphones/earphones/soundsport-in-ear-headphones-samsung-devices.html"
	class="external">
	Bose SoundSport® in-ear headphones – Samsung and Android™ devices</a>, and
	the <a href=
	"https://www.urbanears.com/ue_us_en/reimers#reimers-black-belt" class="external" >UrbanEars
	Reimers Black Belt made for Android</a> headsets. These analog headsets
	must be connected to the device USB port via a USB to Audio
	converter.</p>
	</li>
	</ul>


	<p>Note that in either case, the button must produce virtual key codes for all three of the
	required buttons (volume up, volume down, play/pause) for the test to succeed.
	Refer to the Software mapping section in <a href="/devices/accessories/headset/usb-headset-spec">
	Android USB Headset Accessory Specification</a> for the virtual key codes.</p>


	<table>
	<tr>
	<td width="50%">A USB headset.</td>

	<td width="50%"><img src="/compatibility/cts/images/usb_headset.png" alt=
	"USB headset" width="300" id="usb_headset">
	</td>
	</tr>
	</table>


	<h2 id="required-additional-hardware">Required additional hardware</h2>


	<p>Patch cables (for loopback) 2 short ¼" male to ¼" male patch cables to
	connect the outputs to the inputs of the USB</p>


	<table>
	<tr>
	<td width="50%">¼" male to ¼" male patch cables.</td>

	<td width="50%"><img src="/compatibility/cts/images/patch_cables.png"
	alt="patch cables" width="300" id="patch_cables">
	</td>
	</tr>
	</table>


	<p>USB peripheral cable</p>


	<table>
	<tr>
	<td width="50%">This cable (which typically comes with the peripheral),
	connects the USB audio peripheral to the host device.</td>

	<td width="50%"><img src="/compatibility/cts/images/peripheral_cable.png"
	alt="peripheral cable" width="300" id="peripheral_cable">
	</td>
	</tr>
	</table>


	<p>USB "On The Go" (OTG) adapter</p>


	<table>
	<tr>
	<td width="50%">A USB "On The Go" (OTG) adapter is required to physically
	connect the peripheral to the Android device and indicate to the Android
	device that it should assume the role of "host".</td>

	<td width="50%"><img src="/compatibility/cts/images/otg_adapter.png" alt=
	"OTG adapter" width="300" id="otg_adapter">
	</td>
	</tr>
	</table>


	<p>Analog headphones to monitor the output of the USB audio interface for the
	Play test.</p>


	<table>
	<tr>
	<td width="50%">Set of analog headphones.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/analog_headphones.png" alt="analog headphones"
	width="300" id="analog_headphones">
	</td>
	</tr>
	</table>


	<h2 id="tests">Tests</h2>


	<p>In each test, indicate test success by clicking the <strong>test
	pass</strong> (check mark) button. Otherwise, indicate test failure by
	clicking the <strong>test fail</strong> (exclamation point) button.</p>


	<h3 id="attributes-test">Attributes test</h3>


	<h4 id="abstract">Abstract</h4>


	<p>This test verifies that the attributes (supported sample-rates, channel
	configurations, sample formats, etc.) match the set of a-priori known attributes
	of the device.</p>


	<h4 id="process">Process</h4>


	<p>After invoking the test from the main menu, connect a USB audio
	peripheral. If the attributes match, the <strong>test pass</strong> (check
	mark) button will be enabled.</p>


	<table>
	<tr>
	<td width="50%">Select <em>USB Audio Peripheral Attributes
	Test.</em></td>

	<td width="50%"><img src="/compatibility/cts/images/attributes_test.png"
	alt="attributes test" width="300" id="attributes test">
	</td>
	</tr>


	<tr>
	<td width="50%">Summary of instructions is displayed.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/attributes_summary.png" alt=
	"attributes summary" width="300" id="attributes_summary">
	</td>
	</tr>


	<tr>
	<td width="50%">Pre-connect screen.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/attributes_preconnect.png" alt=
	"attributes preconnect" width="300" id="attributes_preconnect">
	</td>
	</tr>


	<tr>
	<td width="50%">USB audio peripheral connected to Android Device with
	peripheral cable and OTG adapter.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/attributes_connected.png" alt=
	"attributes connected" width="300" id="attributes_connected">
	</td>
	</tr>


	<tr>
	<td width="50%">Post-connect screen.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/attributes_postconnect.png" alt=
	"attributes post connection" width="300" id="attributes_postconnect">
	</td>
	</tr>
	</table>


	<h3 id="play-test">Play test</h3>


	<h4 id="abstract">Abstract</h4>


	<p>This test verifies that audio playback is functioning. It does this by
	generating a 1KHz test tone and presenting it in stereo (two-channels) to the
	USB audio peripheral.</p>


	<h4 id="process">Process</h4>


	<p>After invoking the test from the main menu, connect the USB audio
	interface, including the analog headset, to the headset output jack on the
	interface for monitoring.</p>


	<p>Press the <strong>PLAY</strong> button. If the test tone is heard in both
	channels of the headset, indicate test pass by clicking the <strong>test
	pass</strong> (check mark) button. If either or both of the channels do not
	play the tone, indicate test failure by clicking the <strong>test
	fail</strong> (exclamation point) button.</p>


	<h4 id="notes">Notes</h4>


	<table>
	<tr>
	<td width="50%">Select <em>USB Audio Peripheral Play Test.</em></td>

	<td width="50%"><img src="/compatibility/cts/images/play_test.png" alt=
	"play test" width="300" id="play_test">
	</td>
	</tr>


	<tr>
	<td width="50%">Summary of instructions is displayed.</td>

	<td width="50%"><img src="/compatibility/cts/images/play_summary.png"
	alt="play summary" width="300" id="play_summary">
	</td>
	</tr>


	<tr>
	<td width="50%">Pre-connect screen.</td>

	<td width="50%"><img src="/compatibility/cts/images/play_preconnect.png"
	alt="play preconnect" width="300" id="play_preconnect">
	</td>
	</tr>


	<tr>
	<td width="50%">
	Connect the USB audio peripheral to the Android Device.

	<p>The headphones are connected to the headphone output jack on the USB
	audio interface for monitoring.</p>
	</td>

	<td width="50%"><img src="/compatibility/cts/images/play_connected.png"
	alt="play connected" width="300" id="play_connected">
	</td>
	</tr>


	<tr>
	<td width="50%">Post-connect screen.</td>

	<td width="50%"><img src="/compatibility/cts/images/play_postconnect.png"
	alt="play post connection" width="300" id="play_postconnect">
	</td>
	</tr>
	</table>


	<h3 id="record-loopback-test">Record (loopback) test</h3>


	<h4 id="abstract">Abstract</h4>


	<p>This test verifies that audio recording is functioning. It does this by
	generating a tone at the outputs of the USB audio interface, which is then
	routed via patch cords to the inputs of the USB audio peripheral.</p>


	<h4 id="process">Process</h4>


	<p>After invoking the test from the main menu, connect the USB audio
	interface. Connect the analog outputs to the analog inputs with patch cables.
	Press the <strong>RECORD LOOPBACK</strong> button. If both the channels of
	the recorded test tone are shown in the view below, indicate test pass by
	clicking the <strong>test pass</strong> (check mark) button. If either or
	both of the channels does not display, indicate test failure by clicking the
	<strong>test fail</strong> (exclamation point) button.</p>


	<h4 id="notes">Notes</h4>


	<p>Ensure positive connection of both input and output jacks on the
	peripheral. It will be necessary to adjust the input levels to correctly
	display the recorded signal.</p>


	<table>
	<tr>
	<td width="50%">Select <em>USB Audio Peripheral Record Test.</em></td>

	<td width="50%"><img src="/compatibility/cts/images/record_test.png" alt=
	"record test" width="300" id="record_test">
	</td>
	</tr>


	<tr>
	<td width="50%">Summary of instructions is displayed.</td>

	<td width="50%"><img src="/compatibility/cts/images/record_summary.png"
	alt="record summary" width="300" id="record_summary">
	</td>
	</tr>


	<tr>
	<td width="50%">Pre-connect screen.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/record_preconnect.png" alt="record preconnect"
	width="300" id="record_preconnect">
	</td>
	</tr>


	<tr>
	<td width="50%">USB audio Interface with loopback connected to Android
	device.</td>

	<td width="50%"><img src="/compatibility/cts/images/record_connected.png"
	alt="record connected" width="300" id="record_connected">
	</td>
	</tr>


	<tr>
	<td width="50%">Connections on the back of the USB audio interface.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/record_connected_back.png" alt=
	"record connected in back" width="300" id="record_connected_back">
	</td>
	</tr>


	<tr>
	<td width="50%">Connections on the front of the USB audio interface.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/record_connected_front.png" alt=
	"record connected in front" width="300" id="record_connected_front">
	</td>
	</tr>


	<tr>
	<td width="50%">Post-connect screen.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/record_postconnect.png" alt=
	"record post connection" width="300" id="record_postconnect">
	</td>
	</tr>
	<tr>
	<td width="50%">Post-connect screen, with record test running.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/record_postconnect_running.png" alt=
	"record postconnect running" width="300" id="attributes_postconnect_running.">
	</td>
	</tr>
	</table>


	<h3 id="headset-buttons-test">Headset buttons test</h3>


	<h4 id="abstract">Abstract</h4>


	<p>This test verifies the <strong>media/transport</strong> buttons on the
	recommended headset are correctly recognized.</p>


	<h4 id="process">Process</h4>


	<p>After invoking the test from the main menu, connect the USB headset
	peripheral. Press each <strong>media/transport</strong> (play, pause, volume
	up & volume down) button on the headset. As each is recognized, it will be
	recognized in the test panel. When all buttons have been recognized, the
	<strong>test pass</strong> (check mark) button will be enabled. Click the
	<strong>test pass</strong> button to indicate success. If the full set of
	buttons is not recognized, indicate test failure by clicking the <strong>test
	fail</strong> (exclamation point) button.</p>


	<h4 id="notes">Notes</h4>


	<table>
	<tr>
	<td width="50%">
	The USB headset peripheral connected to the Android device.

	<p>Note the OTG adapter.</p>
	</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/buttons_connected.png" alt="buttons connected"
	width="300" id="buttons_connected">
	</td>
	</tr>


	<tr>
	<td width="50%">Select <em>USB Audio Peripheral Buttons Test.</em></td>

	<td width="50%"><img src="/compatibility/cts/images/buttons_test.png"
	alt="buttons test" width="300" id="buttons_test">
	</td>
	</tr>


	<tr>
	<td width="50%">Summary of instructions is displayed.</td>

	<td width="50%"><img src="/compatibility/cts/images/buttons_summary.png"
	alt="buttons summary" width="300" id="buttons_summary">
	</td>
	</tr>


	<tr>
	<td width="50%">
	Peripheral connected, but no buttons recognized (yet).

	<p>Note that the expected (buttons which are known to the device
	profile) are indicated with white text; those that are not part of
	the test peripheral are displayed in grey text.</p>
	</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/buttons_not_recognized.png" alt=
	"buttons not recognized" width="300" id="buttons not recognized">
	</td>
	</tr>


	<tr>
	<td width="50%">Peripheral connected, and expected buttons
	recognized.</td>

	<td width="50%"><img src=
	"/compatibility/cts/images/buttons_recognized.png" alt=
	"buttons recognized" width="300" id="buttons recognized">
	</td>
	</tr>
	</table>
	</body>
	</html>