DATA COMMUNICATION OVERVIEW

1.1 Objectives
The objectives of post
i)                  What is Data Communication ?
ii)                Various data transmission codes
iii)               How data is encoded?
iv)              Various Modulation techniques

  1.2 Introduction
Communication plays a very important part in our lives because we are almost always involved in some form of communication, e.g.

• A face-to-face conversation
• Reading a book
• Sending or receiving a letter
• A telephonic conversation
• Watching a film or T. V.
• Looking at paintings in an art gallery
• Attending a lecture

There are many other examples of communications and Data Communications is one specific area of whole field of communication.
Aim of communication is to transfer some information from one point to another.
In data communication, this information is generally called as Data or a message.
1.2.1 Components
In order to send data/message from one point to another, following three components are must:

1. Source
2. Medium
3. Receiver

Components
These elements are the minimum requirement for any communication process.

Remote Terminals

In data communication, source and receiver data is called Data Terminal Equipment (DTE), e.g. a teleprinter or a computer terminal with keyboard. The medium may be a 2W telephone line or 2W/4W leased line. Let us see a simple data network (Fig.2).

It involves a computer. One or more terminals (Remote Terminals) connected to the computer via communication lines.