ELSA MicroLink 56k PCI (Conexant)

Actually it can be used, but a company called Linuxant is selling closed-source drivers for the internal modems using the connexant chips.

Beta drivers works fine. You have to look up for it. Free (as in beer) drivers now are only 14.4kbps.

See http://www.linuxant.com/ if you’re interested.

The price is $19,95.