Unfortunately, all USB modems on the market currently claim to require
Windows - so I have no way of knowing which, if any, will work.

A Creative Labs Modem Blaster USB worked - but I can't find any store that
sells them.  A Zoom "USB mini" doesn't work.

Can anyone suggest USB modems known to work with umodem?  Ideally, known to
work as of 1.5.2.

-s