Source : Free On-Line Dictionary of Computing

Group 3
     
         (G3) The {CCITT} fax {protocol} which
        uses data {compression} and allows a variety of file types
        (e.g. {electronic mail}, pictures, {PostScript}) to be
        transmitted over {analogue} telephone lines.
     
        The Group 3 protocol was published by {CCITT} in 1993.  Full
        details of the protocol are available from {ITU-T}.
     
        See also {Group 4}.
     
        (1998-10-03)