This is from the Mer Mail install guide - it may or may not be what you're looking for.
Configuring the U.S. Robotics Sportster 14.4 modem as a local modem
1 Power off the modem.
2 Set the DIP switches 1, 3, 7, and 8 Down for all programming. (All other switches should be Up.)
3 Power on the modem.
4 Enter the commands below from the administration terminal to configure the modem:
The administration terminal should be set to either 2400 bps or 9600 bps (that is, Meridian Mail console speed).
AT&F0 <Return> (response is OK)
ATS0=1 <Return> (response is OK)
AT&B1 <Return> (response is OK)
ATY0 <Return> (response is OK)
ATQ1 <Return> (no response)
AT&W0 <Return> (no response)
AT&W1 <Return> (no response)
5 Power off the modem.
6 Set the DIP switches 1, 4, and 8 down. (All others switches should be up.)