< protocol , compression > (G4) The CCITT fax protocol which uses data compression and allows a variety of file types (e-mail, pictures, PostScript , etc.) to be transmitted over digital ( ISDN ) telephone lines.
The Group 4 protocol was published by CCITT in 1993. Full details of the protocol are available from ITU-T .
See also Group 3 .
(1998-09-10)