Satellite networks in the isdn era

Abstract

AbstractThe concept of an integrated service digital network (ISDN) is becoming topical for the evolution of world‐wide telecommunications. In fact the consultative committees (CCITT and CCIR) have worked actively on the definition of the ISDN and its functions, and many PTTs and other operating companies are engaged in programmes aimed at introducing digital transmission and switching in the public switched telephone network (PSTN) with a view to establishing the first versions of an ISDN.Satellites are well prepared to operate in an ISDN environment.The present competition with fibre optics and other terrestrial carriers may perhaps limit the initial contribution of satellites to the establishment of trunk routes in the first ISDNs, but in the medium term the particular characteristics of flexible distribution of information over very large areas may become of fundamental importance, and many satellite‐based networks developed independently may give concrete support to the ISDN. In the long term satellites may experience an even deeper degree of integration, by providing part of the switching facilities of the ISDN on board.