<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.
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Nearby terms: gronked « group « Group 3 « Group 4 » Group Code Recording » group identifier » Group Separator