Data Communication

What is data communications?

    Data communications (DC) is the process of using computing and communication technologies to transfer data from one place to another, and vice versa and also it can be define as a process of transferring data electronically from one place to another.

 Now Lets see what are the basic requirements need for successful communication. 

• There should be at least two or more parties (Sender and receiver).
• There should be a communication medium (channel).
• There should use of Compatible Standards (Protocols)

 The basic components of data communications are as follows.

1. Message (Data)

• The message is the data or information to be communicated. It may consist of text, number, pictures, sound, video or any a combination of these.

    2. Sender

• Sender is a device that sends data. The data can consist of text, numbers, pictures etc. it is also called source or transmitter.

    3. Receiver

• Receiver is a device that get the data sends by the sender. It is also called sink. The receiver can be computer, printer or another computer related device. The receiver must be capable of accepting the data.

    4.  Medium

• Medium is the physical path that connects sender and receiver. It is used to transmit data. The medium can be a copper wire, a fiber optic cable, microwaves etc. It is also called communication channel.

   5.   Protocol

• is a system of rules that allow two or more entities of a communication system to transmit information via any kind of variation of a physical quantity

    6.  Encoder and Decoder

• The encoder is a device that converts digital signals in a form that can pass through a transmission medium. The decoder is a device that converts the encoded signals into digital form. The receiver can understand the digital form of message. Sender and receiver cannot communicate successfully without encoder and decoder.

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        Characteristics of Data Communication System. There are four main Characteristics of the Data communication.

1. Delivery.
         The system must deliver data to the correct destination. Data must be received by the intended device or user and only by that device or user.

2. Accuracy.
             The system must deliver the data accurately. Data that have been altered in transmission and left uncorrected are unusable.

3. Timeliness.
            The system must deliver data in a timely manner. Data delivered late are useless. In the case of video and audio, timely delivery means delivering data as they are produced, in the same order that they are produced, and without significant delay. This kind of delivery is called real-time transmission.

4. Jitter.
            Jitter refers to the variation in the packet arrival time. It is the uneven delay in the delivery of audio or video packets. For example, let us assume that video packets are sent every 3D ms. If some of the packets arrive with 3D-ms delay and others with 4D-ms delay, an uneven quality in the video is the result.