Sierra Wireless AirLink FX100, Руководство пользователя

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4112221 Rev 7.2 June 19, 2013 38
User Guide Interfaces
5.1.2.5. Audio Lines Connection
The FX Series supports one microphone input and one speaker output.
5.1.2.5.1. Microphone
The microphone inputs are connected in differential mode to reject common mode noise and TDMA
noise. The microphone inputs have already included biasing for an electrets microphone (0.5mA and
2V) and are ESD protected. An electret microphone may be directly connected to these inputs
allowing an easy connection to a headset.
The microphone gain can be adjusted by AT+VGT and the transmit digital gain can be adjusted by
AT+WDGT . Refer to documents [1] Open AT Application Framework AT Commands Interface Guide
and [2] AirPrime SL808xT and Q2698 Open AT Framework Commands Interface Guide for more
information about these AT commands.
The following table shows the pin assignments of the microphone input. Note that there is a difference
in the microphone signal names used between FXT009 and FX100.
Table 14. Microphone Pin Description for FXT009
(Sub D
15-pin)
Pin #
Signal I/O I/O Type Description
4 CMIC2P I Analog Microphone positive input
5 CMIC2N I Analog Microphone negative input
Table 15. Microphone Pin Description for FX100
(Sub D
15-pin)
Pin #
Signal I/O I/O Type Description
4 CMIC1P I Analog Microphone positive input
5 CMIC1N I Analog Microphone negative input
Table 16. Equivalent Circuits of CMIC
DC Equivalent Circuit AC Equivalent Circuit