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Appendix C
AT Commands
AT Commands
This Appendix details the "AT" commands used by modems and ISDN TAs. This information
is provided to assist users who are using the Wireless Gateway's serial (RS232 port).
It is not relevant to Cable or DSL modems connected to the WAN (Ethernet) port.
Required Settings
For the Wireless Gateway to use the Serial Port correctly, the modem or ISDN TA must be set
as follows.
Setting
AT Command
Fixed baud rate setting
AT&B1
RTS/CTS flow control
AT&K3
DCD to track the presence of a carrier
AT&C1
DTR off to hang-up modem
AT&D2
DSR always on
AT&S0
If your Modem or ISDN TA uses the commands above, then the
Initial String
would be as
follows:
AT&F&B1&K3&C1&D2&S0X4
Notes:
•
The command "AT&F" is used to set the modem to the factory default settings, to ensure a
consistent starting point.
•
For some Mircocom and other modems, the "ATX4" command is not sufficient - a "W2"
command (no "AT") must be used as well.
•
ISDN TAs may not use these commands; please check your user guide for your ISDN TA.
Finding the current Initial String
If your modem or ISDN TA is already working correctly using the PC's serial port, but you
don’t know what the initialization string is, you can use the following procedure to find out.
1.
Select
My Computer
, then
Dial-Up Networking
.
2.
Select the icon for your connection, then
Properties
.
3.
Click the
Configure
button, then the
Connection
tab, as shown below.
C
