| page.title=3.5 mm Headset Jack: Device Specification |
| @jd:body |
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| <div id="qv-wrapper"> |
| <div id="qv"> |
| <h2>In this document</h2> |
| <ol id="auto-toc"> |
| </ol> |
| </div> |
| </div> |
| |
| |
| <p>To achieve compatibility with the <a href="plug-headset-spec.html">3.5 mm plug |
| headset specification</a>, devices that include a 4 conductor 3.5 mm audio jack |
| must meet the following specifications. For Android compatibility requirements, |
| refer to the <em>Analog audio ports</em> section of the <a |
| href="{@docRoot}compatibility/android-cdd.html#7_8_audio">Android CDD</a>.</p> |
| |
| <h2 id="headset_jack_functions">Functions</h2> |
| |
| <table> |
| <tr> |
| <th>Function</th> |
| <th>Device Support</th> |
| </tr> |
| <tr> |
| <td>Stereo Audio Out</td> |
| <td>Required</td> |
| </tr> |
| <tr> |
| <td>Audio in (Mic)</td> |
| <td>Required</td> |
| </tr> |
| <tr> |
| <td>Ground</td> |
| <td>Required</td> |
| </tr> |
| </table> |
| |
| <h2 id="software_mapping">Software mapping</h2> |
| |
| <table> |
| <tr> |
| <th style="width:33%">Function</th> |
| <th style="width:33%">Device Support</th> |
| <th style="width:33%">Description</th> |
| </tr> |
| <tr> |
| <td>Function A control event</td> |
| <td>Required</td> |
| <td>Input event: <code>KEY_MEDIA</code> |
| <p>Android key: <code>KEYCODE_HEADSETHOOK<code></p></td> |
| </tr> |
| <tr> |
| <td>Function D control event</td> |
| <td>Required</td> |
| <td>Input event: <code>KEY_VOICECOMMAND</code> |
| <p>Android key: <code>KEYCODE_VOICE_ASSIST</code></p></td> |
| </tr> |
| <tr> |
| <td>Function B control event</td> |
| <td>Required</td> |
| <td>Input event: <code>KEY_VOLUMEUP</code> |
| <p>Android key: <code>VOLUME_UP</code></p></td> |
| </tr> |
| <tr> |
| <td>Function C control event</td> |
| <td>Required</td> |
| <td>Input event: <code>KEY_VOLUMEDOWN</code> |
| <p>Android key: <code>VOLUME_DOWN</code></p></td> |
| </tr> |
| <tr> |
| <td>Headset insertion detection</td> |
| <td>Required</td> |
| <td>Input event: <code>SW_JACK_PHYSICAL_INSERT 7</code></td> |
| </tr> |
| <tr> |
| <td rowspan="2">Headset type detection</td> |
| <td>Mic</td> |
| <td>Input event: <code>SW_MICROPHONE_INSERT 4</code></td> |
| </tr> |
| <tr> |
| <td>No Mic</td> |
| <td>Input event: <code>SW_HEADPHONE_INSERT 2</code></td> |
| </tr> |
| <tr> |
| <td rowspan="2">Headset speaker impedance</td> |
| <td>Required Headphone (low)</td> |
| <td>Failure mode is to indicate headphones so limitation would be on</td> |
| </tr> |
| <tr> |
| <td>Required Line In (high)</td> |
| <td>Input event: <code>SW_LINEOUT_INSERT 6</code></td> |
| </tr> |
| </table> |
| |
| <h2 id="mechanical11">Mechanical</h2> |
| |
| <table> |
| <tr> |
| <th style="width:33%">Function</th> |
| <th style="width:33%">Device Support</th> |
| <th style="width:33%">Description</th> |
| </tr> |
| <tr> |
| <td>4 conductor 3.5 mm jack</td> |
| <td>Required</td> |
| <td></td> |
| </tr> |
| <tr> |
| <td>CTIA pinout order (LRGM)</td> |
| <td>Required</td> |
| <td>3 Pin & Mono Plug Compatible</td> |
| </tr> |
| <tr> |
| <td>OMTP pinout order (LRMG)</td> |
| <td>Optional but strongly recommended</td> |
| <td></td> |
| </tr> |
| <tr> |
| <td>Headset detect sequence</td> |
| <td>Required</td> |
| <td>Plug insert notification must be triggered only after all contacts on |
| plug are touching their relevant segments (this prevents unreliable headset |
| detection due to slow insertion.</td> |
| </tr> |
| </table> |
| |
| <h2 id="electrical12">Electrical</h2> |
| |
| <h3 id="general">General</h3> |
| |
| <table> |
| <tr> |
| <th style="width:33%">Function</th> |
| <th style="width:33%">Device Support</th> |
| <th style="width:33%">Notes</th> |
| </tr> |
| <tr> |
| <td>Maximum output voltage drive</td> |
| <td>150mV</td> |
| <td>>= 150mV on 32 ohm |
| <p>Test conditions: EN50332-2</p></td> |
| </tr> |
| <tr> |
| <td>Mic bias resistance</td> |
| <td>Required</td> |
| <td>Flexible on detection method used and microphone bias resistor |
| selection. Require that all button resistance value ranges specified below |
| be detected and related to their respective function</td> |
| </tr> |
| <tr> |
| <td>Mic bias voltage</td> |
| <td>1.8V - 2.9V</td> |
| <td>To guarantee compatibility to common microphone capsules.</td> |
| </tr> |
| </table> |
| |
| <h3 id="function_impedance_and_threshold_detection">Function impedance and |
| threshold detection</h3> |
| |
| <p>Devices must detect the following resistor ladder on the accessories. The |
| accessories will be tested to the standardized circuit diagram in the diagram |
| illustrated earlier (Reference Headset Test Circuit) where the total impedance |
| is measured from MIC terminal to GND when a button is pressed with 2.2V mic |
| bias applied through 2.2 kOhm resistor. This is the same effective resistance |
| as the button detection circuit with the microphone in parallel with the button |
| resistor.</p> |
| |
| <table> |
| <tr> |
| <th style="width:40%">Button Impedance Level</th> |
| <th style="width:20%">Device Support</th> |
| <th style="width:40%">Notes</th> |
| </tr> |
| <tr> |
| <td>70 ohm or less</td> |
| <td>Required</td> |
| <td>[Function A]</td> |
| </tr> |
| <tr> |
| <td>110 - 180 ohm</td> |
| <td>Required</td> |
| <td>[Function D]</td> |
| </tr> |
| <tr> |
| <td>210 - 290 ohm</td> |
| <td>Required</td> |
| <td>[Function B]</td> |
| </tr> |
| <tr> |
| <td>360 - 680 ohm</td> |
| <td>Required</td> |
| <td>[Function C]</td> |
| </tr> |
| </table> |
| |
| <table> |
| <tr> |
| <th style="width:40%">Headset Speaker Impedance Level</th> |
| <th style="width:20%">Device Support</th> |
| <th style="width:40%">Notes</th> |
| </tr> |
| <tr> |
| <td>Low Threshold Detection</td> |
| <td>Required</td> |
| <td>Headphone (low) < 1 Kohm</td> |
| </tr> |
| <tr> |
| <td>High Threshold Detection</td> |
| <td>Required</td> |
| <td>Line In (high) > 5 Kohm</td> |
| </tr> |
| </table> |
| |
| <table> |
| <tr> |
| <th style="width:40%">4-Segment Plug Detection Resistance (between 3rd and 4th segment)</th> |
| <th style="width:20%">Device Support</th> |
| <th style="width:40%">Notes</th> |
| </tr> |
| <tr> |
| <td>4-Segment Plug Threshold</td> |
| <td>Required</td> |
| <td>Resistance >= 100 ohms</td> |
| </tr> |
| <tr> |
| <td>3-Segment Plug Threshold</td> |
| <td>Required</td> |
| <td>Resistance < 100 ohms</td> |
| </tr> |
| </table> |