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close this book Expanding access to science and technology
close this folder Session 2b: The technological experience: information resources and networks
close this folder Communication networks
View the document Abstract
View the document 1. Introduction
View the document 2. The narrow-band ISDN
View the document 3. Broad-band ISDN
View the document 4. Concluding remarks

1. Introduction

ISDN is a fully digitized communication network that is expected gradually to take over the telephone network. ISDN was standardized in detail by the International Telegraph and Telephone Consultative Committee (CCITT), and thus the world-wide connection of ISDN should be easy.

In Japan, ISDN was made available commercially by Nippon Telegraph and Telephone Corporation (NTT) in 1988. Since then, ISDN has been growing and is now available almost all over the country. Multimedia computing is a popular topic among people involved with personal computers and workstations. Multimedia computers are believed to take full advantage of ISDN. In other words, ISDN will promote multimedia communication.

ISDN is based on synchronous transfer mode (STM) technology. To improve multimedia communication features, novel technology, called the asynchronous transfer mode (ATM), is being developed in many countries. CCITT has been standardizing the broad-band ISDN (B-ISDN) on the basis of ATM. One of the most important parts of B-ISDN is the "fibre-to-the-home" (FTTH) concept.

In FITH, optical fibre cables are extended to customer premises; specifically, optical fibres will replace the metallic twisted pairs now being used for subscriber loops. B-ISDN is expected to push telecommunications strongly toward multimedia services, covering up to high-definition TV (HDTV).

This paper describes the state of the art in ISDN and future trends relevant to B-ISDN.