From what you have posted, I'm not sure what type of modem you have, or the make and model.
Have a look through this document. Pay attention to section 2, it explains what a win modem is. My guess is that is what you have.
http://www.tldp.org/HOWTO/Modem-HOWTO.html#toc2
If it is a hardware modem, you do not need a driver. If it's a winmodem, you may have trouble finding a driver.