Lucent Technologies MERLIN LEGEND Release 6.0 Network Reference Manual page 48

MERLIN LEGEND Communications System Release 6.0
Network Reference 555-660-150
1 Introduction
Tandem Trunking and Tandem Switching
case, the call is routed from System C to System A over tandem trunks. At
System A, the call goes out over a facility connected to the PSTN as a local call
from System A.
These two calls have the following features in common:
All or part of each call is carried over tandem trunks.
The calls are routed seamlessly from a system extension to a destination.
The calls can result in substantial savings over the cost of the same calls
using telecommunications service providers and the PSTN.
The users dial the calls normally: one is an inside call and one is an ARS
call made on a System Access (SA) button. ARS and Universal Dial Plan
(UDP) routing are programmed to take advantage of all PSTN facilities in
the network.
In the next sections, we will look at this and other network configurations and
examine more carefully the tandem trunks that link systems in private networks.
Network Configurations
This topic looks at some sample network configurations and the differences
among them. It does not illustrate all of the possible ways that private networks
can be connected.
Figure 1–1, as noted above, shows a series configuration, where systems are
arranged in a line with no central system acting as a hub. In
A and D are peripheral systems, because neither connects to more than one
switch in the network. Note that a series configuration can consist of only two
systems.
Figure 1–2
star configuration .
shows the second possible arrangement for private networks, called a
1
Figure
Issue 1
February 1998
Page 1-6
1–1, Systems