GR 268 CORE : ISSUE 1

Deals with the protocol and procedural requirements on the local switching system for serving Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) customers. It addresses call establishment and clearing procedures for signaling over the user-network interface and interworking with existing networks. Interexchange ISDN calls are not covered except for packet mode calls and those calls that connect to non-ISDN users ie users who are served through analog telephone lines, covered in TR TSY 000444. Calls to non-ISDN users are known as interworking calls. Emphasizes basic call establishment methods such as call setup, call progress treatment, connect, answer and disconnect. Circuit mode and packet mode call methods are detailed. Provides requirements for the National ISDN (NI) platform.