From 7327b8e58b696d66ad874c3c033c3beee3736609 Mon Sep 17 00:00:00 2001 From: Clay Murphy Date: Wed, 29 Oct 2014 18:37:03 -0700 Subject: Docs: Adding audio headset spec and images Bug: 17790168 Change-Id: Ib6aecb37bc3948f1acc862dd61273759df69d63f --- src/accessories/accessories_toc.cs | 13 +- src/accessories/headset-spec.jd | 676 ++++++++++++++++++++++++++++ src/accessories/images/headset-circuit1.png | Bin 0 -> 102755 bytes src/accessories/images/headset-circuit2.png | Bin 0 -> 43239 bytes 4 files changed, 687 insertions(+), 2 deletions(-) create mode 100644 src/accessories/headset-spec.jd create mode 100644 src/accessories/images/headset-circuit1.png create mode 100644 src/accessories/images/headset-circuit2.png diff --git a/src/accessories/accessories_toc.cs b/src/accessories/accessories_toc.cs index d1badbe7..95748f24 100644 --- a/src/accessories/accessories_toc.cs +++ b/src/accessories/accessories_toc.cs @@ -34,8 +34,17 @@
  • Version 1.0
    • -
  • Building Audio Accessories
    • -
  • Building Custom Accessories
    • +
  • +
    + + Audio Accessories + +
    + +
    • +
  • Custom Accessories
    • diff --git a/src/accessories/headset-spec.jd b/src/accessories/headset-spec.jd new file mode 100644 index 00000000..6e9bd69b --- /dev/null +++ b/src/accessories/headset-spec.jd @@ -0,0 +1,676 @@ +page.title=Wired audio headset specification +@jd:body + + +
    +
    +

    In this document

    +
      +
    +
    +
    + +

    This document specifies the requirements for headsets and mobile devices to +function uniformly across the Android ecosystem. It is separated into two +sections beginning with the specifications for the headset +accessory followed by the specifications for the mobile device.

    + +

    Headset Accessory (Plug) Specifications

    + +

    The requirements in the following section apply to the headset accessory.

    + +

    Functions

    + + + + + + + + + + + + + + + + + + +
    +

    Function

    +    		 +

    Accessory Support

    +
    +

    Stereo Audio Out

    +    		 +

    Required

    +
    +

    Audio in (Mic)

    +    		 +

    Required

    +
    +

    Ground

    +    		 +

    Required

    +
    + +

    Control-Function Mapping

    + + + + + + + + + + + + + + + + + + + + + + + + + + + +
    +

    Control Function

    +    		 +

    Accessory Support

    +    		 +

    Description

    +
    +

    Function A

    +    		 +

    Required

    +    		 +

    Play/pause/hook (Short Press), Trigger Assist (Long Press), Next (double press)

    +
    +

    Function B

    +    		 +

    Optional

    +    		 +

    Vol+

    +
    +

    Function C

    +    		 +

    Optional

    +    		 +

    Vol-

    +
    +

    Function D

    +    		 +

    Optional

    +    		 +

    Reserved (Nexus devices will use this reserved function to launch Google Now +voice search)

    +
    + +

    Assign functions to buttons as follows:

    + + + +

    Mechanical

    + + + + + + + + + + + + + + + + + + + + + + + + + + + +
    +

    Function

    +    		 +

    Accessory Support

    +    		 +

    Notes

    +
    +

    4 conductor 3.5mm plug

    +    		 +

    Required

    +    		 +

    Ref: EIAJ-RC5325A standard

    +
    +

    CTIA pinout order (LRGM)

    +    		 +

    Required

    +    		 +

    Except in regions with legal requirements for OMTP pinout

    +
    +

    OMTP pinout order (LRMG)

    +    		 +

    Optional

    +
    +

    Microphone

    +    		 +

    Required

    +    		 +

    Must not be obstructed when operating headset controls

    +
    + +

    Electrical

    + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
    +

    Function

    +    		 +

    Accessory Support

    +    		 +

    Description

    +
    +

    Ear speaker impedance

    +    		 +

    16 ohms or higher

    +    		 +

    Recommend 32 - 300 ohms

    +
    +

    Mic DC resistance

    +    		 +

    1000 ohms or higher

    +    		 +

    Mic characteristics must be compliant with section 5.4 “Audio Recording” of +current Android Compatibility Definition Document (CDD)

    +
    +

    Control Function Equivalent impedance*

    + +

    *Total impedance from positive mic terminal to GND when button is pressed with +2.2 V mic bias applied through 2.2 kOhm resistor

    +    		 +

    0 ohm

    +    		 +

    [Function A] Play/Pause/Hook

    +
    +

    240 ohm +/- 1% resistance

    +    		 +

    [Function B]

    +
    +

    470 ohm +/- 1% resistance

    +    		 +

    [Function C]

    +
    +

    135 ohm +/- 1% resistance

    +    		 +

    [Function D]

    +
    + +

    Reference Headset Test Circuit 1

    + +Reference Headset Test Circuit 1 +

    Figure 1. Reference headset test circuit 1

    + +

    Note: Four-segment plug shows CTIA pinout. For OMTP pinout, please swap MIC and +GND segments

    + +

    Reference Headset Test Circuit 2

    + +Reference Headset Test Circuit 2 +

    Figure 2. Reference headset test circuit 2

    + +

    Note: The second reference circuit above illustrates how the actual resistor values +(R1 - R4) will change based on the microphone capsule resistance to achieve the +equivalent impedance values as required by the specification. The example above +assumes a 5 kOhm microphone impedance. Therefore, as an example, to achieve an +equivalent R4 impedance of 135 Ohm, the actual R4 resistor value needs to be +139 Ohms.

    + +

    Mobile Device (Jack) Specifications

    + +

    The requirements in the following section apply to the 3.5 mm jack on Android +mobile devices.

    + +

    Headset Jack Functions

    + + + + + + + + + + + + + + + + + +
    +

    Function

    +    		 +

    Device Support

    +
    +

    Stereo Audio Out

    +    		 +

    Required

    +
    +

    Audio in (Mic)

    +    		 +

    Required

    +
    +

    Ground

    +    		 +

    Required

    +
    + +

    Software mapping

    + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
    +

    Function

    +    		 +

    Device Support

    +    		 +

    Description

    +
    +

    Function A control event

    +    		 +

    Required

    +    		 +

    input event KEY_MEDIA

    + +

    Android key KEYCODE_HEADSETHOOK

    +
    +

    Function D control event

    +    		 +

    Required

    +    		 +

    input event KEY_VOICECOMMAND

    + +

    Android key KEYCODE_VOICE_ASSIST

    +
    +

    Function B control event

    +    		 +

    Required

    +    		 +

    input event KEY_VOLUMEUP

    + +

    Android key VOLUME_UP

    +
    +

    Function C control event

    +    		 +

    Required

    +    		 +

    input event KEY_VOLUMEDOWN

    + +

    Android key VOLUME_DOWN

    +
    +

    Headset insertion detection

    +    		 +

    Required

    +    		 +

    input event SW_JACK_PHYSICAL_INSERT 7

    +
    +

    Headset type detection

    +    		 +

    Mic

    +    		 +

    input event SW_MICROPHONE_INSERT 4

    +
    +

    Headset type detection

    +    		 +

    No Mic

    +    		 +

    input event SW_HEADPHONE_INSERT 2

    +
    +

    Headset speaker impedance

    +    		 +

    Required Headphone (low)

    +    		 +

    Failure mode is to indicate headphones so that limitation would be on

    +
    +

    Headset speaker impedance

    +    		 +

    Required Line In (high)

    +    		 +

    input event SW_LINEOUT_INSERT 6

    +
    + +

    Mechanical

    + + + + + + + + + + + + + + + + + + + + + + + + + + + +
    +

    Function

    +    		 +

    Device Support

    +    		 +

    Description

    +
    +

    4 conductor 3.5mm jack

    +    		 +

    Required

    +
    +

    CTIA pinout order (LRGM)

    +    		 +

    Required

    +    		 +

    3 Pin & Mono Plug Compatible

    +
    +

    OMTP pinout order (LRMG)

    +    		 +

    Optional but Strongly Recommended

    +
    +

    Headset detect sequence

    +    		 +

    Required

    +    		 +

    Plug insert notification must only be triggered after all contacts on plug are +touching their relevant segments. This will prevent unreliable headset +detection due to slow insertion.

    +
    + +

    Electrical

    + +

    General

    + + + + + + + + + + + + + + + + + + + + + + +
    +

    Function

    +    		 +

    Device Support

    +    		 +

    Notes

    +
    +

    Minimum output voltage drive capacity

    +    		 +

    150mV

    +    		 +

    >= 150mV on 32 ohm

    + +

    Test conditions: EN50332-2

    +
    +

    Mic bias resistance

    +    		 +

    Required

    +    		 +

    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

    +
    +

    Mic bias voltage

    +    		 +

    1.8V - 2.9V

    +    		 +

    To guarantee compatibility to common microphone capsules.

    +
    + +

    Function Impedance and Threshold Detection

    + +

    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.

    + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
    +

    Button Impedance Level

    +    		 +

    Device Support

    +    		 +

    Notes

    +
    +

    70 ohm or less

    +    		 +

    Required

    +    		 +

    [Function A]

    +
    +

    110 - 180 ohm

    +    		 +

    Required

    +    		 +

    [Function D]

    +
    +

    210 - 290 ohm

    +    		 +

    Required

    +    		 +

    [Function B]

    +
    +

    360 - 680 ohm

    +    		 +

    Required

    +    		 +

    [Function C]

    +
    +

    Headset speaker impedance level

    +
    +

    Low Threshold Detection

    +    		 +

    Required

    +    		 +

    Headphone (low) < 1 Kohm

    +
    +

    High Threshold Detection

    +    		 +

    Required

    +    		 +

    Line In (high) > 5 Kohm

    +
    diff --git a/src/accessories/images/headset-circuit1.png b/src/accessories/images/headset-circuit1.png new file mode 100644 index 00000000..c69df98e Binary files /dev/null and b/src/accessories/images/headset-circuit1.png differ diff --git a/src/accessories/images/headset-circuit2.png b/src/accessories/images/headset-circuit2.png new file mode 100644 index 00000000..67bd5b49 Binary files /dev/null and b/src/accessories/images/headset-circuit2.png differ -- cgit v1.2.3