Sierra Wireless AirLink FX100, User Manual

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4112221 Rev 7.2 June 19, 2013 40
User Guide Interfaces
Refer to the following table for the list of recommended microphone characteristics.
Table 19. Recommended Microphone Characteristics
Feature Values
Type Electret 2V/0.5 mA
Impedance
Z = 2k

Sensitivity -40dB to -50dB
SNR > 50dB
Frequency response Compatible with GSM specifications
5.1.2.5.2. Speaker
The speaker outputs are connected in differential mode to reject common mode noise and TDMA
noise.
Speaker outputs are connected to internal push-pull amplifiers and may be loaded down with
components between 32
– 150Ω and up to 1nF. These outputs may be directly connected to a
speaker.
The output power may be adjusted by 2dB steps. The gain of the speaker outputs is internally
adjusted and may be tuned using the
AT+VGR command. Furthermore, the digital gain can be
adjusted using AT+WDGR . 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 speaker output. Note that there is a difference in
the speaker signal name used between FXT009 and FX100.
Table 20. Speaker Outputs Pin Description for FXT009
(Sub D
15-pin)
Pin # Signal I/O I/O Type Description
10 CSPK2P O Analog Speaker positive output
15 CSPK2N O Analog Speaker negative output
Table 21. Speaker Outputs Pin Description for FX100
(Sub D
15-pin)
Pin # Signal I/O I/O Type Description
10 CSPK1P O Analog Speaker positive output
15 CSPK1N O Analog Speaker negative output
Figure 22. Equivalent Circuit of CSPK