3Com AccessBuilder 500, User Manual

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1-4 C
H A P T E R
1: G
E T T I N G
S
T A R T E D
Benefits of ISDN
ISDN is an extension of the national and international public switched
telephone network, which offers a digital end-to-end telecommunication
system, providing a better quality service than available using the analog
telephone network. The principal benefits of ISDN are:
■
Fast call setup times, typically taking less than one second for national
calls.
■
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 and
one 16 Kbps control channel called the D channel. The line service is
presented into the customers premises through a standard RJ45 socket.
A significant aspect of the ISDN service is that it can be provided over
the same wiring that was installed for the original telephone service.
Therefore, ISDN can be made available relatively cheaply almost
anywhere that previously had access to the analog system.
The cost of installation and rental of basic rate ISDN lines has dropped to
the point where it is extremely attractive as regards cost and performance.