When we communicate, we are sharing information. That sharing can be local or remote. Local communication usually occurs face to face, while remote takes place over distance.
- Information are always in terms of DATA.
- Data communication are the exchange of data between to devices via some form of transmission medium such as a wire cable.
- Data refers to information presented in whatever form is agreed upon by parties creating and using the data.
Communication device must be part of a communication system made up of combination of hardware and software.
Effectiveness of data communication depends upon four fundamental characteristics:
- Delivery: The system must deliver data to the correct destination. Data must be received by the intended device or user.
- Accuracy:the system must deliver data accurately. Data that have been altered in transmission and left uncorrected are unusable.
- Timeliness: the system must deliver data in timely manner. Data deliver late are unusable. in the same order that they are produced, and without significant delay. This king of delivery is called real-time transmission.
- Jitter: Jitter refers to the variation in the packet arrival time. It is the uneven delay in the delivery of audio and video packets.
- Message: The message is the information to be communicated. Popular forms of information include text, numbers, pictures, audio and video.
- Sender: the sender is device that sends the data message. It can be a computer, workstation, telephone handset, video camera, and so on.
- Receiver: The receiver is the device that receives the message. It can be a computer, workstation, telephone handset, video camera, and so on.
- Transmission Medium: The transmission is the physical path by which a message travels from sender to receiver. Ex. twisted pair, coaxial cable, fiber-optic cable, and radio waves.
- Protocol: A protocol is a set of rules that govern data communications. It represents an agreement between the communicating devices
- Data are represented in form of bit.E.g. 0 , 1.
- Different bit pattern is known as code.
- Todayâ€™s codding system in Unicode 32 bit.
- Numbers are also represented in bit format.
- Number is directly converted into binary number.
- It is represented in form of matrix of pixel.
- It is continues data. - Used to recording or broadcasting of sound or music.