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FIBOCOM SC138-
NA
Series Hardware Guide
62/88
3.19
Audio
3.19.1
Audio Interface Definition
SC138 series modules support analog audio interfaces with 3 inputs and 3 outputs, and the pin definition
is shown in the following table:
Table 3-20 Audio interface definition
Pin Name
Pin No. I/O
Description
Remarks
SPKR_DRV_P
148
AO
Loudspeaker drive
Load of 8 Ω and power of
800 mW
SPKR_DRV_N
147
AO
Loudspeaker drive output-
CDC_EAR_P
134
AO
Handset
Load of 32 Ω and power of
123 mW
CDC_EAR_N
135
AO
Handset output-
CDC_HPH_L
139
AO
Earphone left channel
output
-
CDC_HPH_REF
138
-
Earphone reference ground -
CDC_HPH_R
137
AO
Earphone right channel
output
-
CDC_HS_DET
140
AI
Earphone plug detection
-
MIC2_IN_P
142
AI
Earphone MIC input+
-
MIC2_IN_N
141
AI
Earphone MIC input-
-
MIC1_N
144
AI
Main MIC differential input-
-
MIC1_P
145
AI
Main MIC differential input+ -
MIC3_IN_N
233
AI
Auxiliary MIC differential
input-
-
MIC3_IN_P
244
AI
Auxiliary MIC differential
input+
-
MIC4_IN_N
252
AI
Auxiliary MIC differential
input-
Unavailable function by
default, and grounding
MIC4_IN_P
248
AI
Auxiliary MIC differential
Unavailable function by