Integrated Services Digital Network: 2b1q, 4b3t, Basic Rate Interface, Bearer Capability, Broadband Integrated Services Digital Network, BT Highway, B

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 21. Chapters: 2B1Q, 4B3T, Basic Rate Interface, Bearer Capability, Broadband Integrated Services Digital Network, BT Highway, B channel, Circuit identification code, Common ISDN Application Programming Interface, DASS1, DASS2, Digital facsimile equipment, Digital Subscriber System No. 1, Digital Subscriber System No. 2, D channel, FTZ 1 TR 6, H.320, H channel, Interconnect User Part, ISDN-oriented Modular Interface, ISDN digital subscriber line, ISDN User Part, LAPDm, Link Access Procedures, D channel, Multiple Subscriber Number, Network termination 1, Non-Facility Associated Signalling, Primary Rate Interface, Q.931, Service Profile Identifier, S interface, T-interface, Telephone User Part, Terminal adapter, Up0-interface, U interface, VB5 interface. Excerpt: Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits of the public switched telephone network. It was first defined in 1988 in the CCITT red book. Prior to ISDN, the telephone system was viewed as a way to transport voice, with some special services available for data. The key feature of ISDN is that it integrates speech and data on the same lines, adding features that were not available in the classic telephone system. There are several kinds of access interfaces to ISDN defined as Basic Rate Interface (BRI), Primary Rate Interface (PRI) and Broadband ISDN (B-ISDN). ISDN is a circuit-switched telephone network system, which also provides access to packet switched networks, designed to allow digital transmission of voice and data over ordinary telephone copper wires, resulting in potentially better voice quality than an analog phone can provide. It offers circuit-switched connections (for either voice or data), and packet-switched connections (for data), in increments of 64 kilobit/s. A major market application for ISDN in some countries is Internet access, where ISDN typically provides a maximum of 128 kbit/s in both upstream and downstream directions. Channel bonding can achieve a greater data rate; typically the ISDN B-channels of three or four BRIs (six to eight 64 kbit/s channels) are bonded. ISDN should not be mistaken for its use with a specific protocol, such as Q.931 whereby ISDN is employed as the network, data-link and physical layers in the context of the OSI model. In a broad sense ISDN can be considered a suite of digital services existing on layers 1, 2, and 3 of the OSI model. ISDN is designed to provide access to voice and data services simultaneously. However, common use reduced ISDN to be limited to Q.931 and related protocols, which are a set of protocols for establishing and breaking circuit switched con