A set of standards for facsimile (fax) machines published by the ITU-T in 1980. Machines conforming to T.4 later became known as Group III. See also facsimile, Group III, ITU-T, T.2, T.3, and T.6.
An ITU standard for Group 3 fax machines that specifies the page dimensions, resolutions and compression scheme. T.4 and T.30, which were introduced in 1980, make up the complete standard for Group 3 fax. See T.6, T.30 and fax.
