This procedure is used to initialize a U.S. Robotics Sportster Modem (9600, 14400, or 28800). The first procedure is for enabling the modem for dialin, and the second is to set the modem up for dial out. There are not many differences, but they are important. NOTE: Before you start, If you are using a U.S. Robotics Sportster 28,800 baud modem, dip switch 8 must be set to on, all other switches must be off .

Enabling a modem for dialin under CDOS:

The following commands(less their comments) need to be sent to the modem. The easiest way to do this would be to set the port as an AUX port and use ADUMB to initialize the modem. Set handshaking to none for this exercise. Don't forget to use the AUX command to use the correct AUX port that the modem is connected to. COM1 is AUX0, COM2 is AUX1, and the first Addon Port is AUX2. You should see an OK after hitting return for each command as an indicator that the modem understood the command.

AT&F (Reset the modem to it's factory defaults)

ATQ2 (Result codes on dialout only)

ATS0=1 (Answer on first ring)

AT&B1 (Serial port same BAUD rate no matter what dial-in BAUD)

AT&C1 (DCD tracks carrier)

AT&D2 (When DTR drops, drop carrier)

AT&H1 (Use CTS handshaking)

AT&R2 (Use RTS handshaking)

AT&S1 (Use DSR when ready for a call)

ATS10=10 (Used if call waiting is on phone line)

ATS13=1 (Used to reset modem when DTR drops)

ATE0 (Turn off command echoing. At this time, you will no longer see any characters echoed back)

AT&W (Store current settings in NVRAM)

Once you have configured the modem don't forget to enable RTS and CTS handshaking on the port, since we set the modem up for that. 

Configuring a modem for dialout using CCITERM:

The following commands(less their comments) need to be sent to the modem. The easiest way to do this would be to set the port as an AUX port and use ADUMB to initialize the modem. Set handshaking to none for this exercise. Don't forget to use the AUX command to use the correct AUX port the modem is connected to. COM1 is AUX0, COM2 is AUX1, and the first Addon Port is AUX2. You should see an OK after hitting return for each command as an indicator that the modem understood the command.

AT&F (Reset the modem to its factory defaults)

ATQ2 (Result codes on dialout only)

ATS0=0 (Don't answer phone)

AT&C1 (DCD tracks carrier)

AT&D2 (When DTR drops, drop carrier)

AT&H1 (Use CTS handshaking)

AT&R2 (Use RTS handshaking)

AT&S1 (Use DSR when ready for a call)

ATS10=10 (Used if call waiting is on phone line)

ATS13=1 (Used to reset modem when DTR drops)

AT&W (Store current settings in NVRAM)

Once you have configured the modem don't forget to enable RTS and CTS handshaking for the port, as that is what we set the modem up for.