Appendix C
AT Commands
AT Commands
C
This Appendix details the "AT" commands used by modems and ISDN TAs. This information is provided to assist users who are using the serial port of LevelOne
It is not relevant to Cable or DSL modems connected to the WAN (Ethernet) port.
Required Settings
For the LevelOne Wireless Broadband Router 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 |
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RTS/CTS flow control | AT&K3 |
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DCD to track the presence of a carrier | AT&C1 |
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DTR off to | AT&D2 |
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DSR always on | AT&S0 |
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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
2.Select the icon for your connection, then Properties.
3.Click the Configure button, then the Connection tab, as shown below.
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