It depends on what modem you purchased, but generally the most important things to confgure are:
Turn echo off
Turn quiet mode on
Set the serial port baud rate
Save the configuration
The echo and quiet mode settings are standard:
AT E0Q1
But the serial port baud rate varies from modem to modem. For a USR, the setting is:
AT &B1 &N6 (for 9600)
For a Rockwell chipset modem, try:
AT +MS 10,0,9600,9600,0,9600
This is v.32bis modulation with no automode, 9600 baud minimum rate, 9600 baud maximum rate, mu-Law encoding and a 9600 baud maximum transmit rate.
You need to attach a PC to the modem, configure it, and then save the values using the &W command. Typically &W0 will store the default configuration value.
If you think that you have it configured properly, turn it off and back on and then make sure that your configuration is still the same:
AT I4 (for USR)
AT &V (for Rockwell)
If it looks good, then plug it back into your Meridian and test it.
Reply to this post if you are having difficulty getting it configured.