There are five primary components in any computer network; and these are also known as DATA COMMUNICATIONS SYSTEM COMPONENTS:
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To transfer information among various users, spread geographically, we require following basic components in computer network for data communication.

  • Computers (Senders and Receivers):

  • These are devices used for sending and receiving the data and information, normally these devices are computers.

  • Communication Devices:

  • These are the devices which help in communication of data.

  • Communication devices are mainly used for connecting sender and receiver with communication channels for data communication.

Followings are some popular communication devices.


MODEM stands for Modulator Demodulator.

MODEM is coding and decoding device that when data is transmitted from one computer to another computer over a distance through a telephone line or other communication channel then MODEM converts the computer digital signals into signals which can be transmitted on telephone line and vice a versa.

MODEM is mainly used for connecting computers, geographically, distributed over a large distance for data communication.modem unlocking codes click here

Most important use of MODEM is connecting home computer to internet servers.

MODEM is also used for connecting an employee of a company with the computer network from a remote location.

MODEM is categorised according to its speed and some other features like analog or digital MODEM, internal or external MODEM.

Analog MODEMs are known as dial-up MODEM and these are used for connecting home computers with Interner.

Speed of a MODEM normally ranges from a few kbps to mbps.

Digital MODEMs are known as ISDN MODEMs.

These are high speed MODEMs and normally used at places where more large of users are connected through same communication channel.

Speed of digital MODEMs is measured in mbps.


Multiplexer is a device that enables several devices to share common communication channel.

A multiplexer scans multiple devices to collect and transmit data on a single communication line to the appropriate destination.

The multiple devices are polled together and periodically asked whether there is any data to transmit.

This function may be very complex and in some systems there is a separate computer processor devoted to this activity and that is called a front-end processor.

Front End Communication Processor:

These are the programmable devices, which control the function of a large computer system in a network.

This device supports the operation of a mainframe computer by performing functions which otherwise would required to be performed by performed by mainframe itself.

These function include authentication of user by checking his user id and password, coding and decoding of data and control of transmission lines.

Due to use of front-end processor, the mainframe computer dedicates its entire time to its key function that data processing.

Finally, front-end processor performs allied functions like user aunthentication, data encryption, etc in a communication network of large computer based system.

Front end processor is like an assistant to main frame computer.

Protocol Converters:

A hardware device that changes the protocol of one system to the protocol of another.

For Example: If you want to connect an IBM data communication network to AT and T data communication network then the protocol convertor converts the message formats one network system to another so that these are compatible for communication with each other.

It is similar to a person who translates for two persons who do not speak each other language.


A device that connects two networks with each other that are using the same protocol.


A device that connects two or more networks with each other having same network protocol.

A device also helps to select the best route for data communication when there are multiple paths between them.router unlocking click here


A device that connects two or more dissimilar networks that the networks having different protocols.

This device allows networks of different vendors to communicate each other by translating one vendor's protocol into another, gateway is a combination of router and protocol converter.


Repeater is a device, which simply repeats the incoming signal for outgoing communication on channel but with increased strength.

Repeater is also known as amplifier, it amplify the incoming signal for long distance communication.

Remote Access Device:

This device contains a bank of modem that a collection of modems to serve as central point for access of data from various distant or remote locations

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