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A call made between subscriber areas is called a long-distance call, and
can be made by dialing an area code, an exchange number, and a sub-
scriber number.
Subscriber
exchange
Subscriber area A
Fig. 1-25 Subscriber Area and Long-Distance Call
The network for local calls is the local network. And the line and the
exchange for these calls are called the local line and the local exchange.
The network for long-distance calls is toll network. And the line and the
exchange for the long-distance call are called the toll line and the toll
exchange.
A toll exchange is classified into three ranks: toll centers, district centers,
and regional centers.
Toll line
Local line
Fig. 1-26 Structure of Telephone Network
• Regional center (RC)
RCs have been established in Sapporo, Sendai, Tokyo, Nagoya, Kanazawa,
Osaka, Hiroshima, and Fukuoka.
BASIC OF TELEPHONE
Long-distance call
Subscriber
exchange
Subscriber area B
1
2
3
4
5
6
ït
çi
Regional center (RC)
District center (DC)
Toll center (TC)
End office (EO)
Subscriber
1–21
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