What is Integrated Services Digital Network (ISDN)?

Integrated Services Digital Network (ISDN)

            The ISDN is a networking Concept providing for the integrated of voice, video and data services using digital transmission media combining both circuit and packet switching techniques. ISDN was firs launched in Singapore in 1990. ISDN is a type of telephone service, which is an alternative to another computer at a speed, which is faster than even faster than even fastest Modem. If ISDN is available in our area, we should consider it as an alternative to using a Modem with a regular phone line.

          

  ISDN has following features:

·                    Processing of various types of voice, video, data etc.

·                    Transmission and processing of digital data

·                    E-mail box

·                    Tel-conference

·                    Tele-fax, video-fax etc.

ISDN is a type of telephone service, which is an alternative to a regular phone line. The great advantage of ISDN for us is that it allows use to connect to another computer at a consider it as an alternative to using mode regular phone line.

            ISDN services are delivered in one of 2 ways:

1.                  Basic Rate Interface (URL).

2.                  Primary Rate Interface (PRI).

BRI is for home and small business where as PRI is an expensive, large scale service suitable of big company needing to connect many computers and devices.

            One ISDN line provides a number of channels each of which offers a specific amount of bandwidth. Here, bandwidth refers to the capacity to transmit information. A BRI provides three channels:

·                    2 B channels and

·                    1 D channel

B channels carry the bulk of data via computer connections, voice conversations, and fax transmissions and so on. B stands for bearer channel. If offers bandwidth of 64 KBPS. We combine 2 B channels to give up to 128 KBPS.

            The D channel is used for control of ISDN itself. It is used for sending the set up and signaling information back and forth between the telephone system and our devices. The name “D Channel stands for Data Channel”. Actually it carries the internal ISDN data. Our data is actually carried on the B Channels. It has 16 KBPS, however it is used by ISDN itself and so it is not available for use with a computer or telephone.

            A ISDN adapter has to be connected at both end (one at transmitting end and one at receiving end) of the connection in order to use this ISDN connection.

           

            ISDN truly represents the next generation of the world’s telephone service for all forms of telecommunications, including voice.