Applicant: Motorola, INC
2.8 Audio Interface
The module supports the following audio devices:
Two single-ended biased analog microphone inputs for use in a variety of modes.
Two differential mono analog speaker outputs for use in a variety of modes.
A digital serial interface using PCM coding.
TABLE 7 – Audio Interface signals
Handset Microphone Port
The handset microphone port is the module's power-up default active audio input for voice calls. It is
located on pin 61 at the interface connector, named MIC.
It is designed as a single-ended input and should be referenced to the module analog ground.
The microphone input includes all the necessary circuitry to support a direct connection to an external
microphone device. It incorporates an internal bias voltage of 1.8V through a 2.2KΩ resistor, and has an
impedance of 1KΩ.
Headset detection signal
Headset microphone signal / Differential Microphone
Handset microphone signal / Differential Microphone
Differential Loud speaker (negative)
Differential Loud speaker (positive)
Handset differential speaker (negative)
Handset differential speaker (positive)
Digital audio receive
Digital audio transmit
Digital audio clock
Digital audio frame sync.
Motorola General Business Use
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FCC ID: IHDP56JE1
C24 Hardware Interface Manual