3Com 3C892 - OfficeConnect ISDN Lan Modem Router, User Manual

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This chapter provides a description of basic networking concepts and terminology
to help you better understand the key functionality of the ISDN LAN Modem.
What is a network?
A network is a set of computers and other devices such as printers, modems, and
scanners that are connected together either directly via physical cables or indirectly
via dial-up telephone services. A network can be in the same room, the same
building covering a local area, or geographically dispersed covering a wide area.
What is a LAN? A Local Area Network (LAN) is two or more computers linked together in a
contained location such as an office building. By linking the computer together,
and creating a LAN, users can share files and share access to printers.
To physically create a LAN, each computer must be linked together using some
type of cabling. Typically, Ethernet cabling is used. There are three main types of
Ethernet networks: 10BASE-T, 10BASE-2 and 10BASE-5. The ISDN LAN Modem
supports four 10BASE-T connections.
A 10BASE-T Ethernet network is used in small networks with only a few dozen
devices closely located. The physical connection for a 10BASE-T Ethernet network
is over a twisted pair cable. The connector used for 10BASE-T looks similar to the
connector used for your telephone. A 10BASE-5 Ethernet network is used in large
networks with many devices where transmissions occur over distant geographic
areas. A 10BASE-2 (Thin) Ethernet network is used in smaller networks with all
devices being relatively close together.
Figure 53
Example of a LAN
What is a WAN? A Wide Area Network is the result of the connection of two or more LANs,
typically using dial up telephone services via a modem and usually over far
geographic distances.
10 Mbps Ethernet LAN
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