Audio Interface; Handset Microphone Port - Motorola C24 CDMA 1X Hardware Interface Manual

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
Pin (s) Signal Name
55 HDST_INT_N
57 HDST_MIC
59 AGND
61 MIC
63 ALRT_N
65 ALRT_P
67 SPKR_N
69 SPKR_P
18 PCM_DIN
20 PCM_DOUT
22 PCM_CLK
24 PCM_FS
2.8.1

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.
Description
Headset detection signal
Headset microphone signal / Differential Microphone
(positive)
Audio Ground
Handset microphone signal / Differential Microphone
(negative)
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.
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C24 Hardware Interface Manual
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