Ah, looks like you have an Intel modem - often a company will repackage a modem from another manufacturer and put their name on the box. lspci always tells the truth.
You should probably contact the helpful people at linmodems.org:
They created a program called "scanmodem" which will give you advice on which driver to use. If the output is confusing you can send a copy of the ModemData.txt file it creates to firstname.lastname@example.org
and they will help you.