Digi CM - Manual (Page 86)

Configuring For Dial-In Modem Access
86 Chapter 11
Modem init string - The default modem init string is q1e0s0=2. The init string
sets the modem to quiet mode, echo off, and Auto Answer on two rings.
The modem init string is used for initializing an external modem attached to
a Digi CM serial port. See your modem user manual for more information.
Callback - For security reasons, the callback feature can be activated.
If callback is enabled, the Digi CM does not accept any incoming calls.
After the incoming call is rejected, a callback is initiated to the phone num-
ber configured in the “Dial-in modem callback phone number”.
Modem test - To ensure the proper functionality of the modem, the Digi CM
has the ability to test the modem connection in a configurable interval.
The modem test allows you to specify a phone number and an interval.