Checkout the two url's below,everything for setting up modems
If you have any WinModem in your hardware, goto BIOS setup on your computer and
For general info on linux compatible modems.
If you can't reach the below url's, right click, copy model and go onto Google and paste.
I have had good luck with the Actiontec PCI Call Waiting modem in Linux.
For model: Actiontec PC1156012-01cw pci internal
For model: Actiontec EXV156012-01 external