A set of very simple GPL'ed shell scripts that act as a CUPS backend
for a serial faxmodem. Essentially, you print with lpr and the fax is
sent. The nice thing is that you have CUPS around, and this means, for
instance, that you can check whether your fax has been sent just using
your favorite browser (as you would do for any other printer), even if
the faxmodem is really on a remote server. There is also a companion
PPD file that allows to set several options from CUPS web interface,
kprinter, or XPP.
There are two additional packages for the fax systems Hylafax and
efax, fax4CUPS-hylafax and fax4CUPS-efax. Install the one
corresponding to your fax system.