programs to send and receive fax messages

 efax is a small ANSI C/POSIX program that provides the data transport
 function for fax applications using any Class 1 or Class 2 fax modem
 Another program, efix, converts between fax, text, bitmap and grayscale
 formats. fax, a shell script, provides a simple user interface to the efax
 and efix programs. It allows you to send text or Postscript files as faxes
 and receive, print or preview received faxes.
 .
 The ghostscript package is needed to fax Postscript files, and an image
 viewing program like xloadimage is needed to view incoming faxes.
 .
 Note that you probably have to adapt /etc/efax.rc to your needs.