1. How Circuit-Switched Digital
Web presentation GROUP C
ISDN
LAN (Local Area Network)
Central Office Switches
Modem
How Circuit-Switched Digital – p.1/6

2. ISDN
Digital communication network that integrates and
treats telephone, fax, and data communication.
ISDN provides a high-speed, high-quality line service
by digitalizing existing Public Switched Telephone
Networks connected with the modem.
How Circuit-Switched Digital – p.2/6

3. LAN (Local Area Network)
LAN is Local Area Network.It is a network of the
connection of the computer and the printer, etc.
It has three definitions.First,we can exchange informa-
tion between various equipment in the limited region
.Second,the user who introduces it becomes a subject,
and it manages and it manages it. Third,the equip-
ment made by a different vender can be connected
with LAN, and it is possible to communicate mutually.
How Circuit-Switched Digital – p.3/6

4. Central Office Switches
Central office switch is the generic name for the net-
work element in the PSTN that establishes tempo-
rary connections between two subscribers.It is a voice
switch that resides in the central office (CO) of an
ILEC, CLEC, or IXC.
How Circuit-Switched Digital – p.4/6

5. Modem
Modem (from modulator-demodulator) is a device that
modulates an analog carrier signal to encode digital in-
formation, and also demodulates such a carrier signal
to decode the transmitted information. The goal is to
produce a signal that can be transmitted easily and de-
coded to reproduce the original digital data. Modems
can be used over any means of transmitting analog sig-
nals, from driven diodes to radio
How Circuit-Switched Digital – p.5/6

6. References
• e-Words
URL:http://e-words.jp/w/ISDN.html
• Wikipedia
URL:http://ja.wikipedia.org/wiki/
• Hill2dot0
URL:http://www.hill2dot0.com/
How Circuit-Switched Digital – p.6/6