The 64 kbps switched digital network

Abstract

The switched telephone networks (PSTN) today enjoy the benefits of fully mature techniques that have been deployed now for many years. These techniques are essentially the digital technologies used for transmission and switching which have led to ISDN and Information Technologies (IT), associated with the concepts of the Intelligent Network, for controlling network resources and services. The first part of this chapter deals with the main architectural elements of PSTN/ISDN and the services offered.

Although the primary function of PSTN is, of course, to transport voice traffic, it has also become, with the growth of the Internet, the IP traffic access collector for this network via modems of various bit rates, up to 56 kbps for analogue access and 128 kbps for digital access. This interconnection is described in more detail in chapter 19, but here it will be shown how cooperation between PSTN and the Internet via an Intelligent Network can produce a promising synergy between services over the two networks. Finally, using France as a case in point, this chapter looks at the various issues involved in interconnecting telephone networks arising from the opening up of competition between operators. These include carrier selection, number portability and the unbundling of the local loop.