ISDN Services

ISDN services generally fall into three catageries. They are bearer services, teleservices and supplementary services.

Bearer services. ISDN works on the principle of transport services known as bearer services. The bearer service offers the capability to transport digital voice or nonvoice services using this standard. The basic operation of the bearer service is the 64 kbps channel capacity. Bearer services provide the means to transfer information (voice, data and video) between users. The network does not need to process the information. Bearer service belongs to the first three layers of OSI model. These services can be provided with circuit switched, packet switched, frame switched or cell switched networks.

Tele services. In this service, the network may change or process the contents. This service correspond to layers 4-7 of the OSI model. Tele services include telephony, telefax, videofax, telex and teleconferencing.

Supplementary services. It provides additional functionality to the bearer service and teleservices. Supplementary services include call waiting, Reverse charging, and message handling.

Tele services Bearer services

Tele services Bearer services

Isdn Bearer
Fig. 12.1. Conceptual view of ISDN. The conceptual view of ISDN is shown in Fig. 12.1.

The objective of ISDN was introduced in 1979. The concept is the digital end to end connectivity to support a wide range of services. The reason for this concept is the obsolescence and cost prohibitive nature of the analog technology. ISDN uses the existing networks to provide the above discussed services. To access to the various services, the user had to subscribe to a particular network.

The existence of integrated networks will allow for user management of the entire telecommunications functions through the single thread to the outside world. Hence ISDN provide the user with easy access to multiple service over a single connection to the network.

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  • janice
    What are teleservices in isdn?
    4 years ago
  • Wiseman
    What is tele service in isdn?
    4 years ago

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