How to check modem compatibility

Okey i have installed peanut linux and everytime i have had linux i have had eathernet so the net would like just work.
This time i have to use NoCharge internrt/Dial-up and i have been trying to get it to work but maby it is my modem is not compatible is there any way to check and does sum 1 no how to make an internet connectionon peanut linux because it is beatiing the hell outa me i am tryin please any ideas appreciated i will try almost all unless i already have but if you know how please help and TY...