Introduction to Communication:

Communication means exchange of ideas, views, opinion, understanding, feelings, emotions, facts or information between two or more persons by any sources or medium.

Telecommunication:

Telecommunication is the exchange of information over significant distances by electronic means. Mobile phones, land lines, satellite phones and voice over Internet protocol (VoIP) are all telephony technologies -- just one field of telecommunications. Radio, television and networks are a few more examples of telecommunication.

Data Communication:

Data communication refers to the electronic transmission of any type of electronic information encompasses telephone communication, the transmission of television signals, electronic mail and so on.

Data communication is the movement of encoded information from one point to another by means of electrical or optical transmission systems, such systems often are called data communication network.

Basic elements of data communication:

Following are the basic elements of data communication.

1. Source / Sender: Originator of the message. It is an electronic device which is responsible for sending information. Example: Telephone, Computer, Mobile etc.
2. Data Communication Device: It is a device which accepts the data from source sending device and converts it into such a form (analog signal) that can be transmitted over communication channels. Example: Computers with modem.
3. Communication Medium: The path through which the message flows. To transfer the information from one place to another "carriers are needed", and in a computer network these carriers are generally of two types: i) Guided communication medium: In this type of medium wires are used to transfer the data. Example: Twisted pair cable, Co-axial cable and Fiber optics cable ii) Unguided communication medium: This is wireless medium. Example: Radio waves, Microwaves and Satellite communication.
4. Sink / Receiver: The mechanism that accepts the message. It is used to accept the signals of communication system and convert them in understandable form. Generally receiver is a computer with modem.
5. Communication Protocol: Protocol is a software i.e, set of rules which are used to establish communication between several computers. It defines the exact order in which two machines exchange data with one-another.