Table of Contents
Advertisement
BASIC OF TELEPHONE
5.3.2 Toll network
The toll network is formed by three classes of star networks connected
with upper centers and lower centers. The topmost centers form a mesh
network. The nationwide toll network hierarchy of toll networks is called
the toll band system.
There are two kinds of transit trunk. One is the normal transit trunk, which
connects upper and lower centers in the nationwide hierarchy. The other is
the traversal trunk, which ignores this hierarchy and connects two centers
to handle a great deal of calls. For this reason, there are actually many con-
nection routes, and the quality of a conversation is affected by which route
is taken to connect a call.
1–24
Transit trunk
Traversal trunk
Fig. 1-30 Toll Network
Yesterday's
route
I could hear
you better
yesterday.
Fig. 1-31 Actual Connection Route
Regional center
District center
Toll center
End office
Today's
route
Advertisement
Table of Contents
