Imagicle Digital Fax (any version).
How to set fax rate/max speed (in bps) of modems in Digital Fax service for incoming/outgoing faxes
After logging in the Digital Fax server with local administrative rights, you can use either the script method or the manual method described below.
4. Save and restart Digital Fax service from web interface
To limit the speed at 9600 bps set the value to 3.
To limit the speed at 4800 bps set the value to 2.
To limit the speed at 2400 bps set the value to 0.