This Recommendation defines the procedures used by Group 3 facsimile terminals as defined in ITU-T Rec. T.4. These procedures enable documents to be transmitted on the general switched telephone network, international leased circuits and the Integrated Services Digital Network (ISDN). Further, these procedures allow communication to be manual or automatic and for document transmission to be requested alternatively with telephone conversation. With this revision, the colour spaces defined in ITU-T Rec. T.30 will be aligned with those in ITU-T Rec. T.44. Additionally, the scope and applicability of T.30 and T.44-based facsimile applications are expanded. The following methods are defined for introducing T.44 YCC colour space to T.30. 1) New negotiation bit 119 T.44 colour space is added with new Note 83. 2) Note 39 (for bit 74 custom illuminant) and Note 40 (for bit 75 custom gamut range) are modified to reflect the addition of bit 119.