Data Communications

Now communication is not an impossible thing. With the development of science and technology, communication continues to grow. Formerly communication can only be done locally, then evolved to be able to do remote communication (mail, telegraph, telephone). After that, the development of technology not just stop, now we can even communicate with people in other parts quickly using e-mail, SMS, social media. Then we also can communicate with each other, see the other person's face through a video call. So communication (individual-individual) can be done locally and remote.

Data communications derived from the word ‘telecommunication’ and ‘data’. The term 'telecommunication' means communication at a distance (tele is Greek for 'far'). Then the 'data' means of information in any form agreed by the group that make and use the data. So the Data Communications are the exchange of data between two devices through multiple forms of transmission media. In order for communication to occur, communication devices should be part of a communication system consisting of a combination of hardware and software (program).

The effectiveness of a data communication system is highly dependent on the fundamental characteristics, namely:

1. Delivery: The system must be appropriate to send data to a predetermined destination. Data must be received on and only by the user intended.
2. Accuracy: The accuracy of the data sent is very important, because the data that corrupt (inaccurate) is useless.
3. Timeliness: The system must be able to send data on time, late data is not useful.
4. Jitter: Refers to the variation of packet arrival time.

The data communications system has 5 components:

 

1. Sender: Device to send data. For examples computers, phones and others.
2. Receiver: Device to receive data. For examples computer, phone, etc.
3. Message: The information that can be communicated in the form of images, video, sound, text, and numbers.
4. Transmission Medium: physical path through which the message from the sender to the receiver, like coaxial cable.
5. Protocol: An arrangement of rules that govern data communications. It is represented by the agreement between communication devices.

As mentioned previously, now the information can be text, images, numbers, voice and video. The flow of data / information between two devices can be simplex, half-duplex, or full-duplex.

Simplex

Communication between the two devices in which communication can only occur in one direction, namely from the device acts as a sender to the receiver device (Of the two communication devices is only one that can send data and the other can only receive). Example: Keyboard and Traditional Monitor.

Half-Duplex

Communication between two devices where two-way communication can occur, but not at the same time. Example: Walkie-talkies.

Full-Duplex

Communication between two devices where two-way communication can occur at the same time. Example: The telephone network.

The positive response please.

Thanks For Your Attention.

Source: Forouzan, B. Data Communications and Networking 4^th ed. New York, NY: McGraw-Hill,2007.