ITU-T T.4

This Recommendation defines the characteristics of Group 3 facsimile terminals which enable black and white documents and also optionally colour documents to be transmitted on the general switched telephone network, international leased circuits and the Integrated Services Digital Network (ISDN). Group 3 facsimile terminals may be operated manually or automatically and document transmission may be requested alternatively with telephone conversation. The procedures used by Group 3 facsimile terminals are defined in ITU-T Rec. T.30. This revised version consolidates features previously approved as amendments to the text as well as recently approved capabilities, including: support of all standardized image resolutions; support of mixed raster content for black and white images; definitions for transmission of sYCC colour space using facsimile protocol.