2. what are data components?
3. What is Data Representation?
4. What is a Data flow?
1 . What is Data communication?
When we communicate, we are sharing information. This sharing can be local or remote. Between individuals, local communication usually occurs face to face, while remote communication takes place over distance. The term telecommunication, which includes telephony, telegraphy, and television, means communication at a distance.
The term data means information presented in any form by the parties creating and using the data.
Data communication is the exchange of data between two devices through some type of transmission medium such as a wire cable. The Data communications system depends on four fundamental characteristics:- Delivery, Accuracy, Timeliness, and Jitter.
A . Delivery:- The system must deliver data to the correct destination. The data should be received by the same device or person to whom the data is sent.
B . Accuracy:- The system should send data accurately.
C . Timeliness:- The system must deliver data in a timely manner. Data delivered late are useless. Data should reach the receiver in time. 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 significant delay. This kind of delivery is called real-time transmission.
D . Jitter:- Jitter refers to the variation in the packet arrival time. It is the uneven delay in the delivery of audio or video packets. example, let us assume that video packets are sent every 10 ms. If some of the packets arrive with a 10-ms delay and others with a 20-ms delay, an uneven quality in the video is the result.
2. What are the components
Five components of Data communication:-
1 . Massage:- The message is the information (data) to be communicated. Popular forms of information include text, numbers, pictures, audio, and video.
2 . Transmission medium:- The transmission medium is the physical path by which a message travels from sender to receiver. Some examples of transmission media include twisted-pair wire, coaxial cable, fiber-optic cable, and radio waves.
3 . Sender:- The sender is the device that sends the data message. It can be a computer, workstation, telephone handset, video camera, and so on.
4 . Receiver:- The receiver is the device that receives the message. It can be a computer, workstation, telephone handset, television, and so on.
5 . 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.
3 . Data Representation:-
Data representation is a different form such as text, numbers, images, audio, and video.
Text:- In data communications, the text is represented as a bit pattern, a sequence of bits (0s or 1s).
Number:- Numbers are also represented by bit patterns. The number is directly converted to a binary number to simplify mathematical operations.
Images:- Images are also represented by bit patterns. In its simplest form, an image is composed of a matrix of pixels, every pixel is a small dot. The size of the pixel depends on the revolution. For example, an image can be divided into 1000 pixels or 10,000 pixels. In the second case, there is a better representation of the image (better resolution), but more memory is needed to store the image.
Audio:- Audio refers to the recording or broadcasting of sound music. Audio is by nature different from text, numbers, images, or images. It is continuous, not discrete.
Video:- Video refers to the recording or broadcasting of a picture or movie. Video can either be produced as a continuous entity.
4 . Data Flow:-
Communication between two devices can be simplex, half-duplex, or full-duplex.
Simplex:- In simplex mode, the message can go from one side only and cannot come from another side. And messages can only be received. it is a one-way road. keyboards and traditional monitors are examples of simplex devices. The simplex mode can use the entire capacity of the channel to send data in one direction.
Half-Duplex: – In half-duplex mode, each station can both transmit and receive, but not at the same time. When one device is sending, the other can only receive it, and vice versa.
The half-duplex mode is like a one-lane road with traffic allowed in both directions. When cars are traveling in one direction, cars going the other way must wait. In a half-duplex transmission, the entire capacity of a channel is taken over by whichever of the two devices is transmitting at the time. Walkie-talkies and CB (citizens band) radios are both half-duplex systems.
The half-duplex mode is used in cases where there is no need for communication in both directions at the same time; the entire capacity of the channel can be utilized for each direction.
Full-Duplex:-
In full-duplex mode (also called duplex), both stations can transmit and receive simultaneously. The full-duplex mode is like a two-way street with traffic flowing in both directions at the same time. In full-duplex mode, signals going in one direction share the capacity of the link with signals going in the other direction.
The full-duplex mode is used when communication in both directions is required all the time. The capacity of the channel, however, must be divided between the two directions.
