User Manual

SIM900 EVB User Guide
SIM900-EVB_UGD_V1.01 9 08.12.2009
3.2 Audio Interface
Figure 5: Audio Interface
Headset interface:
Pin Signal I/O Description
1 MIC1P I Positive microphone input
2 SPK1P O Positive receiver output
3 MIC1N I Negative microphone input
4 SPK1N O Negative receiver output
Earphone interface:
Pin Signal Input/Output Description
5 MIC2P&SPK2P I/O Auxiliary positive input and output
Line in interface:
Pin Signal Input/Output Description
6 Line in R/L I/O Line in signal