UGC/NTA-NET Exam-2022 General Paper's Topic 8 ICT Notes Part -

Data communication devices

A data communication device provides an interface between computer and the communication channel. These devices are used to transmit, receive, amplify and route data signals across a network through various communication media

.1 Network Interface Card (NIC) 

Network Interface Card (NIC) is a device that enables a computer to connect to a network and communicate. It provides hardware interface between a computer and a network. It can be a separate circuit board that is installed in a computer or a circuit already integrated with the motherboard. 

NIC can prepare, send, receive and control data on the network. It breaks up data into manageable units, translates the protocols of the computer to that of the communication medium and supplies address recognition capabilities.

2 Hub 

A hub is a device used in a wired network to connect computers/devices of the same network. It is a small, simple, passive and inexpensive device Computers/devices are connected to ports of the hub using Ethernet cable. 

When NIC of one computer sends data packets to hub, the hub transmits the packets to all other computers connected to it. 

Each computer is responsible for determining its data packets. The computer for which the data packets are intended accepts it.

3 Switch

 A switch is an intelligent device that connects several computers to form a network. It is a higher performance alternative to a hub. It looks exactly like a hub. 

Switches are capable of determining the destination and redirect the data only to the intended node. Switch performs this by storing the addresses of all the devices connected to it in a table. 

4 Repeater 

A repeater is a device that regenerates incoming electrical, wireless or optical signals through a communication medium . 

Data transmissions through wired or wireless medium can travel only a limited distance as the quality of the signal degrades due to noise. 

Repeater receives incoming data signals, amplifies the signals to their original strength and retransmits them to the destination.

5 Bridge 

A bridge is a device used to segmentise a network. An existing network can be split into different segments and can be interconnected using a bridge. 

This reduces the amount of traffic on a network. When a data packet reaches the bridge, it inspects the incoming packet’s address and finds out to which side of the bridge it is addressed (to nodes on the same side or the other side). 

Only those packets addressed to the nodes on the other side, will be allowed to pass the bridge.

6 Router 

A router is a device that can interconnect two networks of the same type using the same protocol. 

It can find the optimal path for data packets to travel and reduce the amount of traffic on a network. Even though its operations are similar to a bridge, it is more intelligent. 

.7 Gateway 

A gateway is a device that can interconnect two different networks having different protocols

 It can translate one protocol to another protocol.

 It is a network point that acts as an entrance to another network. Its operations are similar to that of a router.

 It can check the device address and the network address and can use algorithms to find the best path for packets to reach the destination. 

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