Data Communication & Computer Network


Data Communication and Computer Networking is the fastest growing sector in all technologies in today’s internet world. Data Communication is defined as the transfer of data between two or more than two devices from one place to another. Data Communication between these remote devices can be achieved from the process called Networking. Networking is the computer science department that includes the connection of Computers, media, and Computer Networking devices. In this tutorial, we will understand about Data Communication components, types of Data representation, creation of data flow, Networking categories (LAN, WAN, etc.) and their functionality, Protocols, and standards, Network models, etc.

What is Data Communication?

Data Communication refers to the sharing of information between local or remote parties. It can be either local (face to face) or remote (take place over distance).

Data Communication is made up of two words as follows:

  • Data- It refers to the information presented by users in any form.
  • Communication- It refers to the exchange of data between two or more devices.

Data Communication is defined as the exchange of data or information between two or more devices through some transmission channels like wire cable, etc. These communication devices made up of a combination of hardware and software.

Further, the word Telecommunication is made up of a combination of two words, “Tele” and “Communication”. Tele is a Greek word that means far and communication means exchange of data or information. So, the exchange of information between two or more than parties that are placed over a distance.

Ex– Telephone, telegraph, and television, etc.

Important characteristics of Data Communication system:

The effectiveness of Data Communication system depends on four characteristics as follows;

  • Delivery

The Data communication system is completely responsible for delivering the data to the correct device or user.

  • Accuracy

The Data communication system is completely responsible for delivering accurate data to the correct device or user.

  • Time

A Data Communication system must deliver real-time data to the intended device or user. If there is any delay in delivering the data by the system, then this data may be useless. This kind of delivery is known as real-time transmission.

  • Jitter

Jitter is defined as the difference between the packet arrival time or uneven delay in the delivery of audio and video packets.

Components of Data Communication:

A Data Communication system comprises five components as follows:

  • Message

The message refers to the data or information to be communicated in forms of text, numbers, pictures, audio, and video, etc.

  • Sender or source

The sender is the device used to communicate the message. For e.g. a camera, computer, mobile, telephone, etc.

  • Receiver or destination

The receiver is the device used to receive the information message sent by the sender. For e.g. computer, television, mobile, etc.

  • Medium

A medium or transmission medium refers to the physical path by which a message or information travels from source to destination or sender to receiver. For e.g. twisted-pair wire, radio waves, optical fiber, coaxial cable, etc.

  • Protocol

A Protocol is defined as the set of instructions used in the Data Communication system. Communication between two or more devices is not possible without protocol; however, these devices may be connected without it. For e.g. A person speaking Chinese can’t communicate with a person who speaks Hindi.

What is Data Representation?

To represent the information or data in different forms such as text, images, audio, video, numbers, etc is called Data Representation.

  • Text: In the Data Communication system, the text is represented by the sequence of bits (0s or 1s). This sequence of bits is called a bit pattern. These sets of bit patterns used to represent text symbols. The process of symbols representation is called coding and each set is called code. The most popular coding system is called Unicode which uses 32 bits to represent a symbol or character in any language. The American Standard Code for Information Interchange (ASCII) constitutes the first 127 characters in Unicode.
  • Numbers: Numbers are also represented by bit patterns. Representations of numbers are not used in the ASCII coding system. Numbers are directly converted into binary form to simplify the mathematical operations.
  • Images: Images refer to the pictorial form of information to be communicated and also represented by bit patterns. An image composed of a matrix of pixels (small dot). The size of an image depends on the parameter called Resolution. To represent a better image, the resolution should be high and needed more space to store that image.

In Images, each pixel is assigned a bit pattern, and the size or value of this pattern depends on the image. Below is the table representing the pixel with respect to the bit pattern as follows.

Bit patterns



Purely Black


Dark Gray


Light Gray


Purely White

By the above table, you can easily understand that if an image made of only Black and White dots, then the 1-bit pattern is used to represent the pixel solely. Further, if any image comprises the Gray scale in its formation, then the 2-bit pattern is used to represent the pixel.

RGB is the most prevailing method used to represent color images. RGB stands for Red Green Blue, as these three colors are primary colors. Each color is made from the combination of these three primary colors. A bit pattern is assigned to each color followed by measuring its intensity.

Further, there is another method used to represent the color images is YCM. It is made from the combination of Yellow, Cyan, and Magenta.

  • Audio: An Audio refers to the message in the form of sound or music. Audio is continuous in nature not discrete. For e.g. Microphone is used to convert the voice or music into an electrical signal.
  • Video: A Video refers to the message in the form of picture or movie. It can be either continuous or discrete in nature. For e.g. Television, camera, etc.