Class 10 Computer Science Note


Data communication

Data communication system is the collection of hardware, software and other devices that allows exchanging data, information and voice between two or more devices through a wire or radio waves.



Telecommunication is a system if transmission of sounds, images, texts or data in the form of electronic signals.


Components of data communications

The components of data communication are as follows:

Data: This is the data that is to be communicated.

Sender: This is the device used to send data.

Medium: This is the device through which the sender makes communication to the receiver.

Receiver: This is the device which receives data sent by the sender.

Protocol: This is the set of rules that are followed nu the sender and the receiver to make communication possible.



Telecommunication is a system if transmission of sounds, images, texts or data in the form of electronic signals.


Computer network

A computer network is a logical or physical interconnection between two or more computers such that they could communicate with each other.


Advantages of computer network

i. A computer networked environment allows faster, easier and reliable transfer of data files from one computer to another.

ii. A network computer allows sharing of networked connected peripherals and simultaneous access to programs and data irrespective of the physical location of the resources and the user.

iii. Computers in network can access the network connected hardware devices like printer, scanner, disk drives etc.


Three models of network

i. Client - Server Network

ii. Peer - to - Peer Network

iii. Centralized Computing Network


Client Server Network

It is a type of network in which each computer in a network is either a client or a server. It is an arrangement where some programs, files or other resources located on one computer called the server but are available to other systems on the network, called clients.



Protocols are the sets of rules that the computer on the network must follow to communicate and to exchange the data with each other.


Names of the protocols

FTP = File Transfer Protocol

SMTP = Simple Mail Transfer Protocol

TCP/IP = Transmission Control Protocol/ Internet Protocol

ARP = Address Resolution Protocol

POP = Post Office Protocol

HTTP = Hyper Text Transfer Protocol


CDP = Cisco Discovery Protocol


Network Interface Card (NIC)

Each computer on any types of network needs a hardware component to control the flow of data. The device that performs this function is Network Interface Card (NIC), commonly called network card.



A network topology refers to the shape of the network in which all the computers are connected together.


Local Area Network (LAN)

A Local Area Network (LAN) is a network of computers that are relatively near to each other and are connected in a war that enables them to communicate by a cable and a small wireless device. A LAN consists of just two or three computers to exchange data or share resources or it can include hundreds of computers of different kinds.


Metropolitan Area Network (MAN)

Metropolitan Area Networks (MANs) are large computers networks spread over a city or neighboring cities. A MAN can have a group of many LANs. Especially, big companies, banks, offices etc. have their branches or sub offices in a city or in neighboring cities. They use MAN to connect with their branches or sub offices for communicating data and information. The communication media in MANs may be optical fiber or unbounded communication media like microwave system, infrared system, radiowave to link their branches and sub offices.


Wide Area Network (WAN)

Wide Area Network is a telecommunications network usually used for connecting computers that spans a wide geographical area. WANs can be used to connect cities, states or even computers. Typically, it will employ communication circuits such as long distance telephone wires, microwaves and satellites. WANs are often used by larger corporations or organizations to facilitate the exchange of data. The world's most popular WAN is the Internet.



MODEM stands for Modulator Demodulator. It is the device that converts digital data to analog form and vice versa. It is a device used to transfer the data of one computer to another using telephone lines.



The signals transmitted become weak due to some problem in the transmission mediums or the distance between the two locations. A repeater is a device that amplifies the incoming signals, creates a new copy of it and transmits the signals on the network. Repeaters are required in the network where computers are a part of each other.



A hub is a hardware device that relays communication data. A hub sends data packets to all devices on a network, regardless of any MAC addresses contained in the data pocket. It is a device with multiple ports that allows network devices to be connected together. It acts as a central networking device in the star topology.


Bus Topology

A bus topology is a network topology in which nodes are connected in a daisy chain by a linear sequence of buses. It is an arrangement of computers on a local area network in which each computer is connected to a central cable through which data is channeled.


Ring Topology

Ring topology is a network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node - a ring. Data travel from node to node with each node along the way handling every packet

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