Summary

Recommendation ITU-T V.153 defines service interworking between two IP domains, whereby one IP domain is using voiceband data over IP (VBDoIP) transport according to Recommendation ITU‑T V.152 and the other IP domain is using facsimile relay over IP (FoIP) transport according to Recommendation ITU-T T.38. Two modes of operation are specified for the T.38‑to‑V.152 interworking function: native versus emulated interworking.

The T.38-to-V.152 interworking technology is subject of the user plane and typically located in IP‑to-IP gateway equipment, like border routers or border gateways.