03-12-2012, 04:14 PM
Data Communication & IP Network
Data_Comm.ppt (Size: 308.5 KB / Downloads: 24)
DATA COMMUNICATION
The word data refers to
facts, concepts and instructions presented in the form agreed upon by the parties creating and using the data.
In the context of computer information systems,
data are represented by binary information units (or bits)
in the form of 0s and 1s.
Data communication:
The exchange of data (in the form of 0s and 1s) between two devices via some form of transmission medium (such as a wire, cable or air).
Local - if the communicating devices are in the same building or a similarly restricted geographical area,
Remote - if the devices are farther apart.
Fundamental characteristics
The effectiveness of a data communication system depends on three fundamental characteristics:
Delivery - of data to the correct destination.
Accuracy- without error or omission
Timeliness
Data delivered late are useless.
Packets should in the same order that they are produced,
Without significant delay.
This kind of delivery is called Real-time Transmission
Components of DATA COM system
Message
The information (data) to be communicated.
text, numbers, pictures, sound, or video or any combination of these.
Sender
The device that sends the data message
computer, workstation, telephone handset, video camera
Receiver
The device that receives the message.
computer, workstation, telephone handset, television