This Recommendation defines the procedures to be applied to allow Group 3 facsimile transmission between terminals where in addition to the PSTN or ISDN a portion of the transmission path used between terminals includes an IP network, e.g., the Internet.

This revision of ITU-T Recommendation T.38 clarifies H.323, H.248.1, SIP and SDP call establishment and improves the compatibility between T.38 gateways and Group 3 facsimile.