The ISDN concentrator-a flexible product for much more than just ISDN

The Belgian Telecom Administration plans to introduce narrowband ISDN (integrated-services digital network) services into its network in the second half of 1988. In the initial phase, the ISDN will consist of three System 12 exchanges with 720 subscribers connected to the basic access and ten lines with primary-rate access. The author outlines the various ways in which the ISDN concentrator can be used. A discussion is also presented of three modules designed for ISDN: the ISN (ISDN subscriber module) for basic access lines, the ITM (ISDN trunk module) for primary rate access and the PCIM (packet channel interface module) for packet handling. Together with the existing supporting modules in S12, these are able to handle the mix of circuit- and packet-mode connections required in an ISDN environment.>