Overview of Data Communication

1

Presented By:

Dr. Madhusudan Maiti Assistant Professor, Dept. of ECE, CGU

Email: madhusudan.maiti@gmail.com,

Paper Code: CS20135

Paper Name: DATA COMMUNICATION & COMPUTER NETWORKS

Introduction to Data Communication

Component of Data Communication

Data flow

Signals: Analog and Digital

Transmission Media

References

OUTLINE

What is Data Communication?

The term telecommunication means communication at

a distance. The word data refers to information

presented in whatever form is agreed upon by the

parties creating and using the data.

Data communications are the exchange of data

between two devices via some form of transmission

medium such as a wire cable.

For data communications to occur, the

communication device must be part of a

communication systems made of a combination of

hardware and software.

Face to Face Communications

Long Distance Communications

Components of a data Communication Systems

Five Components of data communication Systems:

1) Message

2) Sender,

3) Receiver

4) Transmission Medium

5) Protocol

Five Components of data communication Systems

1) Message- It is the information to be communicated. Popular forms of

information include text, picture, audio, video etc.

2) Sender- It is the device which sends the data messages. It can be a

computer, workstation, telephone handset etc.

3) Receiver- It is the device which receives the data message. It can be a

computer, workstation, telephone, handset etc.

4) Transmission Medium- It is the physical path by which a message travels

from sender to receiver. Some examples: twisted pair wire, coaxial cable, optical

fiber etc.

5) Protocol: It is a set of rules that governs the data communications. It

represents an agreements between the communicating devices. Without a

protocol, two devices may be connected but not communicating.

Simple structure communication Systems

Source: Where the data is originated. Source can be Computer, mobile,

communication equipment etc.

Transmitter: Convert data into a suitable form for transmission through the

medium.

Communication System: A medium through which signal is sent.

it may be pair of wire, Co-axial cable, Fiber Optics, LAN, WAN, Internet etc.

Receiver: Which receives the signal and convert it into data or message.

Destination: Where the data is sent.

Destination may be computer, communication equipment,

peripheral device etc.

Source Transmitter

Destination Receiver

Communication Systems

Communication Medium

Co-axial cable

Optical Fiber

DATA REPRESENTATIONS

Information comes in different form such as numbers, text, audio, video, image

Text:

It is represented as a bit pattern, a sequence of bit (0 or 1)..

Text symbol is designed by different set of bit pattern.

ASCIII (American Standard Code for Information Interchange) is used

Numbers:

It is represented by bit patterns.

ASCII is not used to represent numbers..

The number is directly converted to a binary number simplify mathematical

operations.

Images:

Image are also represented by bit patterns.

Audio:

Audio is by nature different from text, numbers, or images.

It is continuous nature, not discrete.

Video: Video is referred to broadcasting od picture, It may be Continuous nature

or discreat nature

Data flow in communication

Data flow in communication

• Only one of the devices on a link can transmit, the other can

only receive.

E.g. Keyboards, Monitors etc.

• Half Duplex: two way alternate

• Each side may sender or receiver but not a same time

Walki-Talki

Data flow in communication

Data flow in communication

• Full Duplex: two-way concurrent

Each side sender and receiver at same time.

Signals

• There are two types of signals to transfer data.

Analog Signals

• An analog signal are continuous and passes through or includes an

infinite number of continuous values along its path. The curve

representing the analog signal passes through an infinite number of

points.

Digital Signals

• A digital signal can have only a limited number of defined values.

Although each value can be any number, it is as simple as 1 and 0.

Transmission Media

• The means through which data is transformed from one place to

another is called transmission or communication media. There are two

categories of transmission media used in computer communications.

• Electromagnetic radiation can be transmitted through an optical media,

such as optical fiber, or through twisted pair wires, co-axial cables, or

dielectric slab waveguides.

• It may also pass through any physical material that is transparent to

the specific wavelength, such as water, air, glass, or concrete. Sound

is, by definition, the vibration of matter, so it requires a physical

medium for transmission, as does other kinds of mechanical wave and

heat energy.

Co-Axial Cable

Fiber Optic Cable

Unguided Media

Reference/ Text Book

1. “Data Communications and Networking” Behrouz A. Forouzan, Tata

McGraw-Hill, 4thEdition.

2. “Computer Networks” A. S. Tannenbum, D. Wetherall, Prentice Hall,

Imprint of Pearson 5thEdition.

3. “Data Communication and Computer Networks”, Ajit Pal, PHI Learning

Pvt. Ltd

4. “Data and Computer Communications” William Stallings, Prentice Hall,

Imprint of Pearson, 9thEdition.

5. “Data Communications and Networking”, White, Cengage Learning

THANK YOU