Page 43 - CA_165_V2.0_C9_Flipbook
P. 43
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, Organisations, 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., online 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 categorised
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 Coaxial Cable
l Fiber Optics Cable
Ethernet
Ethernet is a data link technology for local area networks. It was invented
by an electrical engineer named Robert Metcalfe from the United States.
Ethernet cable refers to CAT5 and CAT6 cables which are connected to an
Ethernet card to a computer.
Such cables commonly provide transmission speed of 100–1000 Mbps. Ethernet cable can be categorised
into Straight Through Ethernet Cable and Ethernet Crossover Cable.
Coaxial Cable
plastic jacket
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 coaxial cable: a 75 Ω standard cable, which
is used in the cable TV industry, and a 52 Ω cable, which is used in
metallic shield
high-speed Internet broadband networks. Such cables are commonly
centre core used in LAN.
Fiber Optics Cable
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

