2. A Computer network is a number if computers
interconnected by one or more transmission paths.
The transmission path often is the telephone line, due to its
convenience and universal preserve.
3. DATA COMMUNICATION
Data Communication is the exchange of data (in the form
of O’s and 1s) between two devices via some form of
transmission medium (such as a wire cable).
4. TYPES OF DATA COMMUNICATION
Data Communication is considered
Local – if the communicating device are in the same
building.
Remote – if the device are farther apart.
5. THE DIFFERENCE BETWEEN DATA
AND INFORMATION
Data: is a representation of facts, concepts and instructions presented
in a formalized manner suitable for communication, interpretation or
processing by human beings or by automatic means.
Information: is currently assigned to data by means by the
conventions applied to those data.
6. FUNDAMENTAL CHARACTERISTICS OF
DATA COMMUNICATION
The effectiveness of a data communication system depends on three characteristics.
Delivery: The system must deliver data to the correct destination.
Accuracy: The system must deliver data accurately.
Timeliness: The system must deliver data in a timely manner.
Jitter : Jitter refers to the variation in packet arrival time.
9. THE MESSAGE
This is the information (Data)to be communicated; it may
be an image, text, number, Audio, or Video.
10. THE SENDER
The sender is device or person that sends the data. It can be
sent using a computer, telephone, or camera.
11. THE RECEIVER
The receiver is device or person that receives the data. It
can be received whether by using a telephone, computer,
television.
12. TRANSMISSION MEDIA
The physical path by which massage travel from source to
destination(sender to receiver) example –twisted pair,
coaxial cable, fiber optic, radio waves.
13. PROTOCOL
A protocol is set of rules that govern data communication.
It provide agreement between sender and receiver devices
14. DATA FLOW
1. Simplex : Communication is unidirectional i.e. TV signal
2. Half Duplex : Either direction but only one way at a time
i.e. waki toki
3. Full Duplex : Both direction at same time. i.e. Phone
15. IN DATA COMMUNICATION FOUR BASIC TERMS
ARE FREQUENTLY USED
In data communication four basic terms are frequently used. They are:
Data : A collection of facts in raw forms that become information after
processing.
Signals : Electric or electromagnetic encoding of data.
Signaling : Propagation of signals across a communication medium.
Transmission : Communication of data achieved by the processing of signals.
