ISDN is a circuit-switched telephone network that provides digital transmission of voice and data over copper wires, offering better voice quality than analog phones. A central office switch, located in a telephone company's central office, switches calls locally or to long-distance carriers through dedicated circuits. A LAN connects computers and printers within the same building using optical fiber to exchange data.

1. How Ccuit-Switched Digital Networks
Work
● ISDN
● The central office switches
● LAN

2. ISDN
ISDN is Integrated Services Digital Network.
ISDN is a circuit-switched telephone network
system, that also provides access to packet
switched networks, designed to allow digital
transmission of voice and data over ordinary
telephone copper wires, resulting in better voice
quality than an analog phone.

3. The central office switches
A central office switch is a large rack of equipment
located in a telephone company's central office that
switches calls locally locally or to long-distance carries
over dedicated circuits.

4. The central office switch
● A central office switch
is a large rack of
equipment
● This is located in a
telephone company's
central office that
switches calls locally
or to long-distance
carriers over
dedicated circuits.

5. The LAN
● Network where
computer and printer
that exists in the same
building by using
optical fiber are
connected,and data is
exchanged.
● There are some kinds
such as
Ethernet,FDDI .

6. Reference
● Wikipedia
● http://ja.wikipedia.org/wiki/
● LAN
● http://www.ktserve.com/lan/lan.html