SPEECH/SIGNALLING OVERLAY

摘要

Where private networks (PABX) are required to be connected together this can be carried out by separation of the signalling and transmission network bearers and using the public network. An interworking unit is used to provide the necessary protocol changes between the private (PABX) and public networks. The signalling can be sent by services such as X.25 packet switching or using the features of an Intelligent Network.