Hmmmm.. not a modem expert but I have configured several PCI modems and many external modems. Unfortunately I have had little or no luck with external USB modems as most of them are software based modems designed for Windows only. Of course there are always exceptions to the rule but it comes down to your pain tolerance. If this is for DSL hispeed, try www.modemsite or www.linmodems.org. If for dialup try the folowing:
1. Check for any options in your dialer for options referring to USB such as /dev/usb/tty/USB0 etc...
2. Check to see if your cdc-acm module is loaded issue this command in terminal -> lsmod
3. If you are relatively new to linux you may want to consider an external serial (not USB) modem. Try BestData, or ActionTec. They are cheap ($5-$10 at local thrift shops) and are almost always guaranteed to be Linux friendly. Don't set connect speed above about 115000 kb/s.
Edited by Trio3b, 02 July 2007 - 10:41 PM.