Hi,
As root you might try
#lspci -v | less
and scroll to the part that describes your modem and see
what it says. This may give you some answers. For instance..
Is this a winmodem? All motherboards I know of and most pci cards that are
not specifically identified as "Dos compatible" or as a "modem controller"
are winmodems. If this is a winmodem it will require a software
driver to allow it to function as a modem... There are several out
there, Google is your friend. If this is the path you must go down, you may wish to start at:
http://linmodems.technion.ac.il/Linmodem-howto.html
for some general information and if your chipset is a conexant:
http://www.linuxant.com/drivers/
If it is linux compatible (an actual hardware Modem) then there are several tools that are useful in setting it up Kppp for instance.
I hope this helps,
Lawrence