Page 213 - Computer_Science_F5

Computer Science both commercial and government-owned. The PSTN system is primarily designed for
voice communication, although it also supports data transmission through modems.

Public Switched Telephone Network

FOR ONLINE READING ONLY

PSTN

Central office

PBX
E1/T1
(E & M)

Regional office

PBX

Figure 3.58: Public Switched Telephone Network

Key components of
PSTN

(a) Local loop:
The physical link
or circuit that
connects from the
demarcation point
of the customer
premises to the
edge of the carrier or
telecommunications
service provider’s
network. Figure 3.59
shows a demarcation
point. Figure 3.59: Dermacation point

204
for Advanced Secondary Schools

Computer Science Form 5.indd 204 23/07/2024 12:33