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It is commonly referred as the ‘Net’. It is a network of networks and the most important component of
today’s Communication and Information Technology. It connects computers and networks of various
individuals, Organizations, Universities, Companies, Government Departments, etc.
It has facilitated e-Commerce, e-Governance, e-Banking, e-Shopping, e-Reservation, e-Chatting,
e-Conferencing, e-Choupal, e-Learning, e-mail, online entertainment activities, web chatting, video-
conferencing, online reservation of tickets of railways, airlines, buses, etc., on-line transactions, online
examinations, getting online information on different topics through search engines, broadcasting of
various television programs.
Media of Communication
Transfer of data for exchanging the information takes place through media can be broadly categorized
into two types:
Wired/Guided
It includes communication that takes place with the help of a solid or wired medium like:
l Ethernet Cable l Co-Axial Cable
l Optical Fiber Cable
Ethernet Cable
Ethernet is a data link technology for local area network. It was invented by
an electrical engineer named ‘Robert Metcalfe’ from United States. Ethernet
cable refers to CAT5, CAT6 cable which is connected to an Ethernet card to
a computer.
Such cables commonly provide transmission speed of 100–1000 Mbps. Ethernet cable can be categorized
into Straight Through Ethernet Cable and Ethernet Crossover Cable.
plastic jacket Co-axial Cable
dielectric insulator It consists of a single conductor surrounded by a circular insulation
layer and a conductive shield. Such cables have a transmission rate
of 100 Mbps with a bandwidth up to 400 Mhz.
There are two types of co-axial cable: a ‘75 Ω’ standard cable, that
metallic shield are used in the cable TV industry and ‘52 Ω’ cable that are used in
high speed internet broadband networks. Such cables are commonly
centre core
used in LAN.
Fiber Optics
This type of cable is used mainly in larger networks in which the data are
transferred through electromagnetic waves. One fiber of such cable can
support over 30,000 telephone lines at a time.
Basics of Information Technology 41

