Many laptops contain winmodems with conexant chipsets. Linuxant provided proprietary drivers for those modems in the past. They were not free software, but you could download them free of charge.
Recently, Linuxant changed this. Now, you only get a crippled version for free, if you want the real drivers, you have to pay.
You can download the last free-of-charge versions here.
Please Note that I don't provide any support for these drivers. They don't work with kernel 2.6 and are probably useless in most cases.
hsflinmodem-5.03.27lnxtbeta03042700.tar.gz
hcfpcimodem-0.99lnxtbeta03042700.tar.gz