What are the concept and medium of data communication?

Concept of data communication system:

Data transfer between a central computer and remote terminals was first introduced in the 1960s. These terminals lacked storage and processing capabilities. Such a method is known as teleprocessing. The terminal of this method is called the silent or dumb terminal. Later, processing and data storage and data storage capabilities were created in these terminals, known as self-contained systems.

Data is a precious resource in today's era. Information or data plays an important role in the improvement of an organization, making realistic decisions for the organization, connecting the internal environment of the organization with the rapidly changing world outside, etc.

The special method by which data is exchanged from one computer to another or more computers is called the data communication method. The advantage of this method is that data can be transmitted quickly and accurately. The main five components or parts of data communication are—

1. source

2. Transmitter

3. Medium

8. Receiver

5. Destination

In this case, one computer can be used as the sender and the other as the receiver. The medium through which information reaches the receiver from the sender is called the medium. Examples of such mediums are telephone lines or cables. Data communication is the process of sending data from a computer to a terminal or from a terminal to a computer. Recently, along with data communication, images, sounds, videos, etc. can also be exchanged with computers. Technologies such as Internet telephony, video conferencing, etc. have further expanded the functions of traditional data communication.

 Source: The computer from which the data is sent is called the source.

Sender: The data coming from the source computer is sent through various communication channels through the local server.

Medium: The medium through which data moves from one place to another is called a medium. For example, fiber optic cable, satellite communication etc.

Receiver: The server through which the data goes to the destination server is called the receiver.

Destination: The computer to which the data is sent from the source is called the destination.

Bandwidth

Bandwidth is the speed at which any Internet Service Provider can allow users to exchange data over a medium in a single period. There are millions of computers connected to the Internet today. ISPs (Internet Service Providers) are businesses that keep their servers connected to the Internet. Their data exchange speed is very high. ISPs rent their internet connections to ordinary users for a fixed fee. The speed at which data can be exchanged between the user's computer and the ISP's computer is called Bandwidth.

Data transmission speed is the rate at which data can be transferred from one place to another or from one computer to another through different media in a single period. Data transfer speed is how many bits of data per second can be transferred by a medium. The speed of data transfer is called Baud Rate. The smallest unit of Baud Rate measurement is bps (Bit per Second). That is, the number of bits transmitted per second is bps. The data transfer speed can be divided into three categories. Namely:

1. Narrow Band

2. Voice Band

3. Broad Band

1. Narrow Band: The speed of data transfer through a narrow band is the lowest. Data transfer speed in such a band is 45 to 300 bps. Narrow band is generally used in applications where low speed is required. For example, a narrow band is used for data transfer through the telegraph.

2. Voice Band: The speed of data transfer in this band is 9600 bps. It is commonly used in local telephone systems. Data is sent from the computer to the printer to another memory device (memory card reader) via the voice band.

3. Broadband: Broadband is used for high-speed data transfer. The broadband data transfer speed is 1Mbps. This type of band is usually used for data transfer through the optical fiber.

Data Transmission Method

Synchronous Data Transfer Method: The method in which data is transferred in block form through a medium is called the synchronous data transfer method. Each block contains at least 80 to 132 characters. The header is attached at the beginning of each block and the Trailer is at the end. The header contains the sender and recipient and indicates the end of the trailer. Data transfer speed is very high in this method. The cost of synchronous data transfer is relatively low. Data buffer registers are required to store data after input. It is initially relatively complex to implement.

Asynchronous Data Transfer Method: The method in which data is transferred one character at a time through a medium is called asynchronous data transfer method. In this method start bit and stop bit are added at the beginning with 7-bit data. Keyboards, modems, etc. transfer data in an asynchronous manner with the CPU. This method does not require data buffer registers to store data after input. It is relatively easy to implement. The speed of data transfer in the asynchronous data transfer method is comparatively very low. Data transfer costs are relatively high. 

Data Transmission Mode: Three modes are mainly used for data transmission, unicast, broadcast, and multicast. There are three types of unicast methods. Namely- 1. Simplex mode 2. Half-Duplex Mode 3. Full-Duplex mode

1. Simplex Mode: The mode in which data can flow only in one direction is called simplex mode. That is, the sender can only send the data to the receiver but the receiver cannot reply. Currently, this method is rarely used for data transmission. Example: Pager system, radio, television broadcast system.

2. Half-Duplex (Half-Duplex) Mode: In this method, data can flow in both directions, but data cannot be sent from both ends simultaneously. That is, both sender and receiver can exchange data but not simultaneously. Example: Walkie-talkie system.

3. Full-Duplex (Full-Duplex) Mode: In this method, data can flow in both directions simultaneously through the same medium. That is, both the sender and receiver can exchange data simultaneously. Example: Telephone system, Internet etc.

Types of Data Transmission Modes (Based on Receiver Data Availability) There are three types of data transmission modes based on receiver data availability. namely

1. Unicast Mode

2. Broadcast Mode

3. Multicast Mode

1. Unicast Mode: The data transmission method in which the data sent by the sender can be received by only one receiver is called unicast mode.

2. Broadcast Mode: The data transmission method in which the data sent by the sender can be received simultaneously by all the receivers is called broadcast mode.

3. Multicast Mode: The data transmission method in which the data sent by the sender can be received by a specified number of receivers is called multicast mode.