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46. Define the following terms:
(a) RJ-45 (b) Ethernet
(c) Ethernet card (d) Hub
(e) Switch
Ans. (a) RJ-45: RJ-45 is a standard type of connector for network cables and networks. It is an 8-pin connector
usually used with Ethernet cables.
(b) Ethernet: Ethernet is a LAN architecture developed by Xerox Corp. along with DEC and Intel. It uses
a bus or star topology and supports data transfer rates of up to 10 mbps.
(c) Ethernet card: The computer parts of Ethernet are connected through a special card called Ethernet
card. It contains connections for either coaxial or twisted pair cables
(d) Hub: In computer networking, a hub is a small, simple, low-cost device that joins multiple computers
together.
(e) Switch: A switch is a small hardware device that joins multiple computers together within one local
area network (LAN).
47. Define the following data communicating devices:
(a) Repeater (b) Bridge
(c) Router (d) Gateway
Ans. (a) Repeater: It is a device that amplifies and restores the signal before it gets degraded and transmits the
original signal back to the destination. A repeater is a regenerator and not an amplifier.
(b) Bridge: A bridge is a device designed to connect two LAN segments. The purpose of a bridge is to filter
traffic on a LAN. Bridge relays frames between two originally separate segments. When a frame
enters a bridge, the bridge not only regenerates the signal but also checks the physical address of
the destination and forwards the new copy only to that port.
(c) Router: Routers operate in the physical, data link and network layers of the OSI model. They decide
the path a packet should take. A router is a networking device whose software and hardware are
usually tailored to the tasks of routing and forwarding data packets across network.
(d) Gateway: A gateway operates on all the seven layers of OSI model. A network gateway is a computer
which has internet-working capability of joining together two networks that use different base
protocols. Gateway converts one protocol to another and can, therefore, connect two dissimilar
networks.
48. What is HTML? Where is it used?
Ans. HTML (Hyper Text Markup Language) is used to create Hypertext documents (web pages) for websites.
HTML is the static mark-up language which is used for the following purposes:
• It is used to create web pages.
• It tells the browser how to display text, pictures and other support media.
• It supports multimedia and new page layout features.
• It provides many tags for controlling the presentation of information on the web pages, such as:
<BODY>, <LI>, <HR>, etc.
49. Define GSM, CDMA and WLL.
Ans. GSM: Global system for mobile communication (GSM) is a wide area wireless communications system
that uses digital radio transmission to provide voice data and multimedia communication services. A
GSM system coordinates the communication between mobile telephones, base stations and switching
systems.
CDMA: Code Division Multiple Access (CDMA) is a digital wireless telephony transmission technique which
allows multiple frequencies to be used simultaneously—Spread Spectrum.
WLL: Wireless in Local Loop (WLL) is a system that connects the subscriber to the public switched telephone
Computer Networks
network (PSTN) using radio signals as alternative to other connecting media.
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