Progress Towards User Access Arrangements in Integrated Services Digital Networks

This paper deals with arrangements for local access to emerging Integrated Services Digital Networks (ISDN´s). The ISDN concept is here introduced as the focal point for the ongoing international activity on multiservice digital networks. ISDN´s are conceived as networks which have evolved from the basic digital telephone networks and they will provide end-to-end digital connectivity to support a wide range of services including voice, data, sound, and video applications. After giving a general outline of the evoving ISDN network scenarios for digital communications, the paper reviews the international trends on user access arrangements in terms of 1) user equipment and interface configurations, 2) access channel structures and information transfer capabilities, 3) local distribution plant configurations (with emphasis on the copper plant), and 4) access protocols.