We all are acquainted with some sorts of communication in our day to day life. For communication of information and messages we use telephone and postal communication systems. Similarly data and information from one computer system can be transmitted to other systems across geographical areas. Thus data transmission is the movement of information using some standard methods. These methods include electrical signals carried along a conductor, optical signals along an optical fibers and electromagnetic areas. Suppose a manager has to write several letters to various clients. First he has to use his PC and Word Processing package to prepare the letter, if the PC is connected to all the client’s PC through networking, he can send the letters to all the clients within minutes. Thus irrespective of geographical areas, if PCs are connected through communication channel, the data and information, computer files and any other programs can be transmitted to other computer systems within seconds. The modern form of communication like e-mail and Internet is possible only because of computer networking.
Basic Elements of a Communication System
The following are the basic requirements for working of a communication system.
1. The sender (source) who creates the message to be transmitted
2. A medium that carries the message
3. The receiver (sink) who receives the message
In data communication four basic terms are frequently used. They are:
Data: A collection of facts in raw forms that become information after processing.
Signals: Electric or electromagnetic encoding of data.
Signaling: Propagation of signals across a communication medium.
Transmission: Communication of data achieved by the processing of signals.
You may be wondering how computers send and receive data across communication links. The answer is data communication software. It is this software that enables us to communicate with other systems. The data communication software instructs computer systems and devices as to how exactly data is to be transferred from one place to another . The procedure of data transformation in the form of software is commonly known as protocol. The data transmission software or protocols perform the following functions for the efficient and error free transmission of data.
1. Data sequencing : Along message to be transmitted is broken into smaller packets of fixed size for error free data transmission.
2. Data Routing : It is the process of finding the most efficient route between source and destination before sending the data.
3. Flow control: All machines are not equally efficient in terms of speed. Hence the flow control regulates the process of sending data between fast sender and slow receiver .
4. Error Control: Error detecting and recovering is the one of the main functions of communication software. It ensures that data are transmitted without any error.
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