In telecommunications, hop on refers to a point at which a signal or call enters a network from another network. For example, a call passing through a private branch exchange (PBX) can hop on to a major network such as AT&T. Conversely, a call coming from a large network can hop on to a local PBX or a local cellular network.
In voice over IP (VoIP), hop on is a point or gateway at which a call moves to an H.323 network from a network that uses some other protocol. H.323 is a communications standard that was accepted in 1996 by the International Telecommunication Union (ITU) to help ensure compatibility in digital transmissions over IP networks.
Hop on is an essential feature of VoIP networks, because it is necessary for the completion of calls to H.323 systems from devices that do not support that protocol, such as conventional phone sets and cell phones.