Basic Rate ISDN (BRI)

Basic Rate ISDN consists of two 64K B channels and 1 16 K D channel. The B channels are used to carry voice or data and the D channel is used for protocol negotiation. Using Multilink PPP (MLP) two ISDN devices are able to negotiate Bonding. This allows them to inverse multiplex the two B channels to achieve 128K throughput. Basic Rate ISDN is delivered over 1 pair of copper to what is known as a U connsection. ISDN devices use an S/T connection for communication. Consequently another device is needed in between. This is an NT1. It uses the U connection to communicate with the phone company switch and has an S;T connection to communicate with your telephone equipment. Most data communications equipment is available with the NT1 built in.

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