Hop off is a term used in telecommunications that refers to a point at which a signal or call leaves a network and moves to another network. For example, a call made on a cell phone set can hop off the local cellular telephone network to a major network such as AT&T. Conversely, a call coming through a major network can hop off that network to a smaller local network or private branch exchange (PBX).
In voice over IP (VoIP), hop off is a point or gateway at which a call moves from an H.323 network to a network that uses some other protocol. H.323 is a communications standard that was accepted in 1996 by the ITU (International Telecommunication Union) to help ensure compatibility in digital transmissions over IP networks.
Hop off is an essential feature of VoIP networks, because it is necessary for the initiation and completion of calls to non-H.323 devices such as conventional hard-wired phone sets and cell phones.