User guide

WA_DEV_FEX20_UGD_002 Rev 004 March 08, 2011 43
Fastrack Xtend User Guide
Interfaces
5.1.2.2. Autobauding Mode
The autobauding mode allows the Fastrack Xtend to detect the baud rate used by the DTE connected
to the RS232 serial link. The autobauding mode is controlled by AT commands. Refer to document [7]
Firmware 7.4a AT Commands Manual (Sierra Wireless Software Suite 2.31)/Firmware 7.4 AT
Commands Manual (Sierra Wireless Software Suite 2.30) for more information.
Note: This feature is not supported in FXT004.
5.1.2.3. Serial Port Auto Shut Down Feature
The RS232 serial link can be shut down when there is no activity between the DTE and the Fastrack
Xtend. This can help improve the power consumption performance.
The Serial Port Auto Shut Down feature is controlled by the AT command AT+WASR. Enter:
 AT+WASR=1 to enter the serial port auto shut down mode
 AT+WASR=0 to exit the serial port auto shut down mode
Refer to document [7] Firmware 7.4a AT Commands Manual (Sierra Wireless Software Suite
2.31)/Firmware 7.4 AT Commands Manual (Sierra Wireless Software Suite 2.30) for more information
on AT commands.
Note: This feature is not supported in FXT004.
Caution: GPIO24 is reserved for serial port auto shut down feature. It is prohibited for customer use.
Improper access to GPIO24 by customers may lead to unexpected behavior on serial port
performance.
It is prohibited to use the serial port auto shut down feature when the CT108-2/DTR is not used in
the application. Otherwise, there will be data lost from the DTE side to the Fastrack Xtend.
5.1.2.4. Audio Lines Connection
The Fastrack Xtend supports one microphone input and one speaker output.
5.1.2.4.1. 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. This electrets 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 [7] Firmware 7.4a AT Commands Manual (Sierra Wireless Software Suite
2.31)/Firmware 7.4 AT Commands Manual (Sierra Wireless Software Suite 2.30) for more information
about these AT commands.
Table 15. Microphone Pin Description
(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