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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, 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.






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