Clay Murphy | 7327b8e | 2014-10-29 18:37:03 -0700 | [diff] [blame] | 1 | page.title=Wired audio headset specification |
| 2 | @jd:body |
| 3 | |
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| 19 | <div id="qv-wrapper"> |
| 20 | <div id="qv"> |
| 21 | <h2>In this document</h2> |
| 22 | <ol id="auto-toc"> |
| 23 | </ol> |
| 24 | </div> |
| 25 | </div> |
| 26 | |
Clay Murphy | 92c38f9 | 2014-10-30 18:19:30 -0700 | [diff] [blame^] | 27 | <p><em>Version 1.0</em></p> |
| 28 | |
Clay Murphy | 7327b8e | 2014-10-29 18:37:03 -0700 | [diff] [blame] | 29 | <p>This document specifies the requirements for headsets and mobile devices to |
| 30 | function uniformly across the Android ecosystem. It is separated into two |
| 31 | sections beginning with the specifications for the headset |
| 32 | accessory followed by the specifications for the mobile device.</p> |
| 33 | |
| 34 | <h2 id=headset_accessory_plug_specifications>Headset Accessory (Plug) Specifications</h2> |
| 35 | |
| 36 | <p>The requirements in the following section apply to the headset accessory.</p> |
| 37 | |
| 38 | <h2 id=functions>Functions</h2> |
| 39 | |
| 40 | <table> |
| 41 | <tr> |
| 42 | <th> |
| 43 | <p><strong>Function</strong></p> |
| 44 | </th> |
| 45 | <th> |
| 46 | <p><strong>Accessory Support</strong></p> |
| 47 | </th> |
| 48 | </tr> |
| 49 | <tr> |
| 50 | <td> |
| 51 | <p>Stereo Audio Out</p> |
| 52 | </td> |
| 53 | <td> |
| 54 | <p><strong>Required</strong></p> |
| 55 | </td> |
| 56 | </tr> |
| 57 | <tr> |
| 58 | <td> |
| 59 | <p>Audio in (Mic)</p> |
| 60 | </td> |
| 61 | <td> |
| 62 | <p><strong>Required</strong></p> |
| 63 | </td> |
| 64 | </tr> |
| 65 | <tr> |
| 66 | <td> |
| 67 | <p>Ground</p> |
| 68 | </td> |
| 69 | <td> |
| 70 | <p><strong>Required</strong></p> |
| 71 | </td> |
| 72 | </tr> |
| 73 | </table> |
| 74 | |
| 75 | <h2 id=control-function_mapping>Control-Function Mapping</h2> |
| 76 | |
| 77 | <table> |
| 78 | <tr> |
| 79 | <th> |
| 80 | <p><strong>Control Function</strong></p> |
| 81 | </th> |
| 82 | <th> |
| 83 | <p><strong>Accessory Support</strong></p> |
| 84 | </th> |
| 85 | <th> |
| 86 | <p><strong>Description</strong></p> |
| 87 | </th> |
| 88 | </tr> |
| 89 | <tr> |
| 90 | <td> |
| 91 | <p>Function A</p> |
| 92 | </td> |
| 93 | <td> |
| 94 | <p><strong>Required</strong></p> |
| 95 | </td> |
| 96 | <td> |
| 97 | <p>Play/pause/hook (Short Press), Trigger Assist (Long Press), Next (double press)</p> |
| 98 | </td> |
| 99 | </tr> |
| 100 | <tr> |
| 101 | <td> |
| 102 | <p>Function B</p> |
| 103 | </td> |
| 104 | <td> |
| 105 | <p>Optional</p> |
| 106 | </td> |
| 107 | <td> |
| 108 | <p>Vol+</p> |
| 109 | </td> |
| 110 | </tr> |
| 111 | <tr> |
| 112 | <td> |
| 113 | <p>Function C</p> |
| 114 | </td> |
| 115 | <td> |
| 116 | <p>Optional</p> |
| 117 | </td> |
| 118 | <td> |
| 119 | <p>Vol-</p> |
| 120 | </td> |
| 121 | </tr> |
| 122 | <tr> |
| 123 | <td> |
| 124 | <p>Function D</p> |
| 125 | </td> |
| 126 | <td> |
| 127 | <p>Optional</p> |
| 128 | </td> |
| 129 | <td> |
| 130 | <p>Reserved (Nexus devices will use this reserved function to launch Google Now |
| 131 | voice search)</p> |
| 132 | </td> |
| 133 | </tr> |
| 134 | </table> |
| 135 | |
| 136 | <p><strong>Assign functions to buttons as follows</strong>:</p> |
| 137 | |
| 138 | <ul> |
| 139 | <li> All one-button headsets must implement Function A. |
| 140 | <li> Headsets with multiple buttons must implement functions according to the |
| 141 | following pattern: |
| 142 | <ul> |
| 143 | <li> 2 functions: A and D |
| 144 | <li> 3 functions: A, B, C |
| 145 | <li> 4 functions: A, B, C, D |
| 146 | </ul> |
| 147 | </ul> |
| 148 | |
| 149 | <h2 id=mechanical>Mechanical</h2> |
| 150 | |
| 151 | <table> |
| 152 | <tr> |
| 153 | <th> |
| 154 | <p><strong>Function</strong></p> |
| 155 | </th> |
| 156 | <th> |
| 157 | <p><strong>Accessory Support</strong></p> |
| 158 | </th> |
| 159 | <th> |
| 160 | <p><strong>Notes</strong></p> |
| 161 | </th> |
| 162 | </tr> |
| 163 | <tr> |
| 164 | <td> |
| 165 | <p>4 conductor 3.5mm plug</p> |
| 166 | </td> |
| 167 | <td> |
| 168 | <p><strong>Required</strong></p> |
| 169 | </td> |
| 170 | <td> |
| 171 | <p>Ref: EIAJ-RC5325A standard</p> |
| 172 | </td> |
| 173 | </tr> |
| 174 | <tr> |
| 175 | <td> |
| 176 | <p>CTIA pinout order (LRGM)</p> |
| 177 | </td> |
| 178 | <td> |
| 179 | <p><strong>Required</strong></p> |
| 180 | </td> |
| 181 | <td> |
| 182 | <p>Except in regions with legal requirements for OMTP pinout</p> |
| 183 | </td> |
| 184 | </tr> |
| 185 | <tr> |
| 186 | <td> |
| 187 | <p>OMTP pinout order (LRMG)</p> |
| 188 | </td> |
| 189 | <td> |
| 190 | <p>Optional</p> |
| 191 | </td> |
| 192 | <td></td> |
| 193 | </tr> |
| 194 | <tr> |
| 195 | <td> |
| 196 | <p>Microphone</p> |
| 197 | </td> |
| 198 | <td> |
| 199 | <p><strong>Required</strong></p> |
| 200 | </td> |
| 201 | <td> |
| 202 | <p>Must not be obstructed when operating headset controls</p> |
| 203 | </td> |
| 204 | </tr> |
| 205 | </table> |
| 206 | |
| 207 | <h2 id=electrical>Electrical</h2> |
| 208 | |
| 209 | <table> |
| 210 | <tr> |
| 211 | <th> |
| 212 | <p><strong>Function</strong></p> |
| 213 | </th> |
| 214 | <th> |
| 215 | <p><strong>Accessory Support</strong></p> |
| 216 | </th> |
| 217 | <th> |
| 218 | <p><strong>Description</strong></p> |
| 219 | </th> |
| 220 | </tr> |
| 221 | <tr> |
| 222 | <td> |
| 223 | <p>Ear speaker impedance</p> |
| 224 | </td> |
| 225 | <td> |
| 226 | <p><strong>16 ohms or higher</strong></p> |
| 227 | </td> |
| 228 | <td> |
| 229 | <p>Recommend 32 - 300 ohms</p> |
| 230 | </td> |
| 231 | </tr> |
| 232 | <tr> |
| 233 | <td> |
| 234 | <p>Mic DC resistance</p> |
| 235 | </td> |
| 236 | <td> |
| 237 | <p><strong>1000 ohms or higher</strong></p> |
| 238 | </td> |
| 239 | <td> |
| 240 | <p>Mic characteristics must be compliant with section 5.4 “Audio Recording” of |
| 241 | current Android Compatibility Definition Document (CDD)</p> |
| 242 | </td> |
| 243 | </tr> |
| 244 | <tr> |
| 245 | <td> |
| 246 | <p>Control Function Equivalent impedance*</p> |
| 247 | |
| 248 | <p>*Total impedance from positive mic terminal to GND when button is pressed with |
| 249 | 2.2 V mic bias applied through 2.2 kOhm resistor</p> |
| 250 | </td> |
| 251 | <td> |
| 252 | <p><strong>0 ohm</strong></p> |
| 253 | </td> |
| 254 | <td> |
| 255 | <p>[Function A] Play/Pause/Hook</p> |
| 256 | </td> |
| 257 | </tr> |
| 258 | <tr> |
| 259 | <td></td> |
| 260 | <td> |
| 261 | <p><strong>240 ohm</strong> +/- 1% resistance</p> |
| 262 | </td> |
| 263 | <td> |
| 264 | <p>[Function B]</p> |
| 265 | </td> |
| 266 | </tr> |
| 267 | <tr> |
| 268 | <td></td> |
| 269 | <td> |
| 270 | <p><strong>470 ohm</strong> +/- 1% resistance</p> |
| 271 | </td> |
| 272 | <td> |
| 273 | <p>[Function C] </p> |
| 274 | </td> |
| 275 | </tr> |
| 276 | <tr> |
| 277 | <td></td> |
| 278 | <td> |
| 279 | <p><strong>135 ohm</strong> +/- 1% resistance</p> |
| 280 | </td> |
| 281 | <td> |
| 282 | <p>[Function D]</p> |
| 283 | </td> |
| 284 | </tr> |
| 285 | </table> |
| 286 | |
| 287 | <h2 id=reference_headset_test_circuit_1>Reference Headset Test Circuit 1</h2> |
| 288 | |
| 289 | <img src="images/headset-circuit1.png" alt="Reference Headset Test Circuit 1" /> |
| 290 | <p class="img-caption"><strong>Figure 1.</strong> Reference headset test circuit 1</p> |
| 291 | |
| 292 | <p class="note"><strong>Note:</strong> Four-segment plug shows CTIA pinout. For OMTP pinout, please swap MIC and |
| 293 | GND segments</strong></p> |
| 294 | |
| 295 | <h2 id=reference_headset_test_circuit_2>Reference Headset Test Circuit 2</h2> |
| 296 | |
| 297 | <img src="images/headset-circuit2.png" alt="Reference Headset Test Circuit 2" /> |
| 298 | <p class="img-caption"><strong>Figure 2.</strong> Reference headset test circuit 2</p> |
| 299 | |
| 300 | <p><strong>Note</strong>: The second reference circuit above illustrates how the actual resistor values |
| 301 | (R1 - R4) will change based on the microphone capsule resistance to achieve the |
| 302 | equivalent impedance values as required by the specification. The example above |
| 303 | assumes a 5 kOhm microphone impedance. Therefore, as an example, to achieve an |
| 304 | equivalent R4 impedance of 135 Ohm, the actual R4 resistor value needs to be |
| 305 | 139 Ohms.</p> |
| 306 | |
| 307 | <h2 id=mobile_device_jack_specifications>Mobile Device (Jack) Specifications</h2> |
| 308 | |
| 309 | <p>The requirements in the following section apply to the 3.5 mm jack on Android |
| 310 | mobile devices.</p> |
| 311 | |
| 312 | <p><strong>Headset Jack Functions</strong></p> |
| 313 | <table> |
| 314 | <tr> |
| 315 | <th> |
| 316 | <p><strong>Function</strong></p> |
| 317 | </th> |
| 318 | <th> |
| 319 | <p><strong>Device Support</strong></p> |
| 320 | </th> |
| 321 | </tr> |
| 322 | <tr> |
| 323 | <td> |
| 324 | <p>Stereo Audio Out</p> |
| 325 | </td> |
| 326 | <td> |
| 327 | <p><strong>Required</strong></p> |
| 328 | </td> |
| 329 | </tr> |
| 330 | <tr> |
| 331 | <td> |
| 332 | <p>Audio in (Mic)</p> |
| 333 | </td> |
| 334 | <td> |
| 335 | <p><strong>Required</strong></p> |
| 336 | </td> |
| 337 | </tr> |
| 338 | <tr> |
| 339 | <td> |
| 340 | <p>Ground</p> |
| 341 | </td> |
| 342 | <td> |
| 343 | <p><strong>Required</strong></p> |
| 344 | </td> |
| 345 | </tr> |
| 346 | </table> |
| 347 | |
| 348 | <h2 id=software_mapping>Software mapping</h2> |
| 349 | |
| 350 | <table> |
| 351 | <tr> |
| 352 | <th> |
| 353 | <p><strong>Function</strong></p> |
| 354 | </th> |
| 355 | <th> |
| 356 | <p><strong>Device Support</strong></p> |
| 357 | </th> |
| 358 | <th> |
| 359 | <p><strong>Description</strong></p> |
| 360 | </th> |
| 361 | </tr> |
| 362 | <tr> |
| 363 | <td> |
| 364 | <p>Function A control event </p> |
| 365 | </td> |
| 366 | <td> |
| 367 | <p><strong>Required</strong></p> |
| 368 | </td> |
| 369 | <td> |
| 370 | <p>input event KEY_MEDIA</p> |
| 371 | |
| 372 | <p>Android key KEYCODE_HEADSETHOOK</p> |
| 373 | </td> |
| 374 | </tr> |
| 375 | <tr> |
| 376 | <td> |
| 377 | <p>Function D control event</p> |
| 378 | </td> |
| 379 | <td> |
| 380 | <p><strong>Required</strong></p> |
| 381 | </td> |
| 382 | <td> |
| 383 | <p>input event KEY_VOICECOMMAND</p> |
| 384 | |
| 385 | <p>Android key KEYCODE_VOICE_ASSIST</p> |
| 386 | </td> |
| 387 | </tr> |
| 388 | <tr> |
| 389 | <td> |
| 390 | <p>Function B control event</p> |
| 391 | </td> |
| 392 | <td> |
| 393 | <p><strong>Required</strong></p> |
| 394 | </td> |
| 395 | <td> |
| 396 | <p>input event KEY_VOLUMEUP</p> |
| 397 | |
| 398 | <p>Android key VOLUME_UP</p> |
| 399 | </td> |
| 400 | </tr> |
| 401 | <tr> |
| 402 | <td> |
| 403 | <p>Function C control event</p> |
| 404 | </td> |
| 405 | <td> |
| 406 | <p><strong>Required</strong></p> |
| 407 | </td> |
| 408 | <td> |
| 409 | <p>input event KEY_VOLUMEDOWN</p> |
| 410 | |
| 411 | <p>Android key VOLUME_DOWN</p> |
| 412 | </td> |
| 413 | </tr> |
| 414 | <tr> |
| 415 | <td> |
| 416 | <p>Headset insertion detection</p> |
| 417 | </td> |
| 418 | <td> |
| 419 | <p><strong>Required</strong></p> |
| 420 | </td> |
| 421 | <td> |
| 422 | <p>input event SW_JACK_PHYSICAL_INSERT 7</p> |
| 423 | </td> |
| 424 | </tr> |
| 425 | <tr> |
| 426 | <td> |
| 427 | <p>Headset type detection</p> |
| 428 | </td> |
| 429 | <td> |
| 430 | <p><strong>Mic</strong></p> |
| 431 | </td> |
| 432 | <td> |
| 433 | <p>input event SW_MICROPHONE_INSERT 4</p> |
| 434 | </td> |
| 435 | </tr> |
| 436 | <tr> |
| 437 | <td> |
| 438 | <p>Headset type detection</p> |
| 439 | </td> |
| 440 | <td> |
| 441 | <p><strong>No Mic</strong></p> |
| 442 | </td> |
| 443 | <td> |
| 444 | <p>input event SW_HEADPHONE_INSERT 2</p> |
| 445 | </td> |
| 446 | </tr> |
| 447 | <tr> |
| 448 | <td> |
| 449 | <p>Headset speaker impedance</p> |
| 450 | </td> |
| 451 | <td> |
| 452 | <p><strong>Required Headphone (low)</strong></p> |
| 453 | </td> |
| 454 | <td> |
| 455 | <p>Failure mode is to indicate headphones so that limitation would be on</p> |
| 456 | </td> |
| 457 | </tr> |
| 458 | <tr> |
| 459 | <td> |
| 460 | <p>Headset speaker impedance</p> |
| 461 | </td> |
| 462 | <td> |
| 463 | <p><strong>Required Line In (high)</strong></p> |
| 464 | </td> |
| 465 | <td> |
| 466 | <p>input event SW_LINEOUT_INSERT 6</p> |
| 467 | </td> |
| 468 | </tr> |
| 469 | </table> |
| 470 | |
| 471 | <h2 id=mechanical11>Mechanical</h2> |
| 472 | |
| 473 | <table> |
| 474 | <tr> |
| 475 | <th> |
| 476 | <p><strong>Function</strong></p> |
| 477 | </th> |
| 478 | <th> |
| 479 | <p><strong>Device Support</strong></p> |
| 480 | </th> |
| 481 | <th> |
| 482 | <p><strong>Description</strong></p> |
| 483 | </th> |
| 484 | </tr> |
| 485 | <tr> |
| 486 | <td> |
| 487 | <p>4 conductor 3.5mm jack</p> |
| 488 | </td> |
| 489 | <td> |
| 490 | <p><strong>Required</strong></p> |
| 491 | </td> |
| 492 | <td></td> |
| 493 | </tr> |
| 494 | <tr> |
| 495 | <td> |
| 496 | <p>CTIA pinout order (LRGM)</p> |
| 497 | </td> |
| 498 | <td> |
| 499 | <p><strong>Required</strong></p> |
| 500 | </td> |
| 501 | <td> |
| 502 | <p>3 Pin & Mono Plug Compatible</p> |
| 503 | </td> |
| 504 | </tr> |
| 505 | <tr> |
| 506 | <td> |
| 507 | <p>OMTP pinout order (LRMG)</p> |
| 508 | </td> |
| 509 | <td> |
| 510 | <p>Optional but <strong>Strongly Recommended</strong></p> |
| 511 | </td> |
| 512 | <td></td> |
| 513 | </tr> |
| 514 | <tr> |
| 515 | <td> |
| 516 | <p>Headset detect sequence</p> |
| 517 | </td> |
| 518 | <td> |
| 519 | <p><strong>Required</strong></p> |
| 520 | </td> |
| 521 | <td> |
| 522 | <p>Plug insert notification must only be triggered after all contacts on plug are |
| 523 | touching their relevant segments. This will prevent unreliable headset |
| 524 | detection due to slow insertion. </p> |
| 525 | </td> |
| 526 | </tr> |
| 527 | </table> |
| 528 | |
| 529 | <h2 id=electrical12>Electrical</h2> |
| 530 | |
| 531 | <h3 id=general>General</h3> |
| 532 | |
| 533 | <table> |
| 534 | <tr> |
| 535 | <th> |
| 536 | <p><strong>Function</strong></p> |
| 537 | </th> |
| 538 | <th> |
| 539 | <p><strong>Device Support</strong></p> |
| 540 | </th> |
| 541 | <th> |
| 542 | <p><strong>Notes</strong></p> |
| 543 | </th> |
| 544 | </tr> |
| 545 | <tr> |
| 546 | <td> |
| 547 | <p>Minimum output voltage drive capacity </p> |
| 548 | </td> |
| 549 | <td> |
| 550 | <p>150mV </p> |
| 551 | </td> |
| 552 | <td> |
| 553 | <p>>= 150mV on 32 ohm</p> |
| 554 | |
| 555 | <p>Test conditions: EN50332-2</p> |
| 556 | </td> |
| 557 | </tr> |
| 558 | <tr> |
| 559 | <td> |
| 560 | <p>Mic bias resistance </p> |
| 561 | </td> |
| 562 | <td> |
| 563 | <p>Required</p> |
| 564 | </td> |
| 565 | <td> |
| 566 | <p>Flexible on detection method used and microphone bias resistor selection. |
| 567 | Require that all button resistance value ranges specified below be detected and |
| 568 | related to their respective function</p> |
| 569 | </td> |
| 570 | </tr> |
| 571 | <tr> |
| 572 | <td> |
| 573 | <p>Mic bias voltage</p> |
| 574 | </td> |
| 575 | <td> |
| 576 | <p>1.8V - 2.9V</p> |
| 577 | </td> |
| 578 | <td> |
| 579 | <p>To guarantee compatibility to common microphone capsules.</p> |
| 580 | </td> |
| 581 | </tr> |
| 582 | </table> |
| 583 | |
| 584 | <h3 id=function_impedance_and_threshold_detection>Function Impedance and Threshold Detection</h3> |
| 585 | |
| 586 | <p>Devices must detect the following resistor ladder on the accessories. The |
| 587 | accessories will be tested to the standardized circuit diagram in the diagram |
| 588 | illustrated earlier (Reference Headset Test Circuit) where the total impedance |
| 589 | is measured from MIC terminal to GND when a button is pressed with 2.2V mic |
| 590 | bias applied through 2.2 kOhm resistor. This is the same effective resistance |
| 591 | as the button detection circuit with the microphone in parallel with the button |
| 592 | resistor.</p> |
| 593 | <table> |
| 594 | <tr> |
| 595 | <th> |
| 596 | <p><strong>Button Impedance Level</strong></p> |
| 597 | </th> |
| 598 | <th> |
| 599 | <p><strong>Device Support</strong></p> |
| 600 | </th> |
| 601 | <th> |
| 602 | <p><strong>Notes</strong></p> |
| 603 | </th> |
| 604 | </tr> |
| 605 | <tr> |
| 606 | <td> |
| 607 | <p><strong>70 ohm or less</strong></p> |
| 608 | </td> |
| 609 | <td> |
| 610 | <p><strong>Required</strong></p> |
| 611 | </td> |
| 612 | <td> |
| 613 | <p>[Function A]</p> |
| 614 | </td> |
| 615 | </tr> |
| 616 | <tr> |
| 617 | <td> |
| 618 | <p><strong>110 - 180 ohm </strong></p> |
| 619 | </td> |
| 620 | <td> |
| 621 | <p><strong>Required</strong></p> |
| 622 | </td> |
| 623 | <td> |
| 624 | <p>[Function D]</p> |
| 625 | </td> |
| 626 | </tr> |
| 627 | <tr> |
| 628 | <td> |
| 629 | <p><strong>210 - 290 ohm</strong></p> |
| 630 | </td> |
| 631 | <td> |
| 632 | <p><strong>Required</strong></p> |
| 633 | </td> |
| 634 | <td> |
| 635 | <p>[Function B]</p> |
| 636 | </td> |
| 637 | </tr> |
| 638 | <tr> |
| 639 | <td> |
| 640 | <p><strong>360 - 680 ohm </strong></p> |
| 641 | </td> |
| 642 | <td> |
| 643 | <p><strong>Required</strong></p> |
| 644 | </td> |
| 645 | <td> |
| 646 | <p>[Function C]</p> |
| 647 | </td> |
| 648 | </tr> |
| 649 | <tr> |
| 650 | <td> |
| 651 | <p><strong>Headset speaker impedance level</strong></p> |
| 652 | </td> |
| 653 | <td></td> |
| 654 | <td></td> |
| 655 | </tr> |
| 656 | <tr> |
| 657 | <td> |
| 658 | <p>Low Threshold Detection</p> |
| 659 | </td> |
| 660 | <td> |
| 661 | <p><strong>Required</strong></p> |
| 662 | </td> |
| 663 | <td> |
| 664 | <p>Headphone (low) < 1 Kohm</p> |
| 665 | </td> |
| 666 | </tr> |
| 667 | <tr> |
| 668 | <td> |
| 669 | <p>High Threshold Detection</p> |
| 670 | </td> |
| 671 | <td> |
| 672 | <p><strong>Required</strong></p> |
| 673 | </td> |
| 674 | <td> |
| 675 | <p>Line In (high) > 5 Kohm</p> |
| 676 | </td> |
| 677 | </tr> |
| 678 | </table> |