a. Components Of Data Communication.
- Message :
The message is the information (data) to be communicated.
e.g text, numbers, pictures, audio, and video.
- Sender :
The sender is the device that sends the data message.
e.g computer, workstation, telephone handset, video camera, and so on.
- Receiver :
The receiver is the device that receives the message.
e.g computer, workstation, telephone handset, television, and so on.
- Transmission medium :
The transmission medium is the physical path by which a message travels from sender to receiver.
e.g transmission media include twisted-pair wire, 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.
Without a protocol, two devices may be connected but not communicating, just as a person speaking French cannot be understood by a person who speaks only Japanese.
These are the main Components of Data Communication.
Note:- After reading the Components of Data Communication its very important to read about data representation.
b. Data Representations:-
Information today comes in different forms such as
represented as a bit pattern i.e a sequence of bits (like 0s and 1s).
Uses 32 bit Unicode and ASCII code representation
represented by bit patterns
Images are also represented by bit patterns.
an image is composed of a matrix of pixels (picture elements), where each pixel is a small dot.
The size of the pixel depends on the resolution.
Combination of colors used for the image representation. Like RGB (red, green and blue) and YCM(yellow, cyan, and magenta)
Audio refers to the recording or broadcasting of sound or music.
Analog and Digital signals are used for audio representation.
Video refers to the recording or broadcasting of a picture or movie.
Video can either be produced as a continuous entity (e.g., by a TV camera), or it can be a combination of images, each a discrete entity, arranged to convey the idea of motion.
Video can be changed to a digital or an analog signal.
Note:- Components of data communication and data representation for data flow.
c. Data Flow:-
Communication between two devices can be of three types i.e simplex, half-duplex, or full-duplex.
- Simplex :
In simplex mode, the communication is unidirectional.
Only one of the two devices on a link can transmit; the other can only receive.
E.g Keyboards and traditional monitors.
- Half-Duplex :
In this type, each station can both transmit and receive, but not at the same time.
When one device is sending, the other can only receive, and vice versa.
E.g Walkie-talkies and CB (citizens band) radios
- Full-Duplex :
Both stations can transmit and receive simultaneously.
The capacity of the channel, however, must be divided between the two directions.
Components of data communication , Data representation and data flow are basic fundamental in data communication chapter