It isn't a question of compatibility with a distro but rather a question of compatibility with Linux itself. I would recommend taking a list of modems w/ you to a flea market, electronics graveyard or what have you and finding a used modem. Is there any local media that has used pc components where you live? They are very common- it just needs to be a hardware modem. Some software modems do work with Linux but AFAIK most any hardware modem should work. As long as it's a 56k hardware modem you should be good to go right?