Define Data Communication and Characteristics

Data communications are the exchange of data between two devices via some
form of transmission medium such as a wire cable. For data communications to occur,
the communicating devices must be part of a communication system made up of a com-
bination of hardware (physical equipment) and software (programs). The effectiveness
of a data communications system depends on four fundamental characteristics: deliv-
ery, accuracy, timeliness, and jitter.

I. 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.
Accuracy.
7 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 signifi-
cant delay. This kind 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 ofaudio or video packets. For example, let us assume that video packets
are sent every 3D ms. Ifsome ofthe packets arrive with 3D-ms delay and others with
4D-ms delay, an uneven quality in the video is the result.