USB modem with linux

I have a Dell Inspiron 7000 laptop with linux installed using libranet 2.0, a debian dist, and it is working fine. Can't get a Diamond Supra Express 56K USB modem to work. I do not have any documentation on this modem. The modem is working fine in window$ 98. Does linux support USB modems? Did anybody get this modem to work with SuSE on a laptop? If you got it working, what version of the kernel did you use? jozien