1-4 CHAPTER 1: GETTING STARTEDBenefits of ISDNISDN is an extension of the national and international public switchedtelephone network, which offers a digital end-to-end telecommunicationsystem, providing a better quality service than available using the analogtelephone network. The principal benefits of ISDN are:n Fast call setup times, typically taking less than one second for nationalcalls.n Greater bandwidth with multiple channels.The basic rate service, often referred to as ISDN 2, carries two 64 Kbps(or possibly two 56 Kpbs in USA) user channels, called B channels andone 16 Kbps control channel called the D channel. The line service ispresented into the customers premises through a standard RJ45 socket.A significant aspect of the ISDN service is that it can be provided overthe same wiring that was installed for the original telephone service.Therefore, ISDN can be made available relatively cheaply almostanywhere that previously had access to the analog system.The cost of installation and rental of basic rate ISDN lines has dropped tothe point where it is extremely attractive as regards cost and performance.
