What are the types of data transmission methods?

Data Transmission System

Asynchronous Transmission:

A data transmission system in which characters are transmitted from sender to receiver is called asynchronous transmission. In this method the sender does not require any primary storage medium for data transmission.

Main features of asynchronous data transmission:

(i) The sender does not require any primary storage device for data transmission.

(ii) In this method of data transmission the sender can transmit the data at any time and the receiver can also transmit it.

(iii) In this method of data transmission, the time between the transmission of one character and the transmission of another character may vary rather than be equal.

(iv) Each character has a start bit at the beginning and end transmission is also called start/stop transmission.

Advantages, Disadvantages and Uses of Asynchronous Data Transmission

Advantages of asynchronous data transmission:

(i) At any time the sender can send data and the receiver can receive it.

(ii) Data transmission requires the sender to have some primary storage device

(iii) Its installation cost is very low.

(iv) Does not require expensive hardware.

(v) This method is convenient for one-way data transmission.

(vi) Data can be sent easily.

(vii) Character can be easily determined from the data received.

Disadvantages of asynchronous data transmission:

(i) Data transmission speed is low.

(ii) Its efficiency is lower than synchronous transmission.

(iii) The medium is unused if the data transmission is stopped, which is very expensive in the case of microwave or satellite.

(iv) Error detection in data transmission is difficult.

(v) This transmission does not take place over long distances.

Uses of Asynchronous Data Transmission:

(a) From the keyboard to the computer

(b) Punch card reader to computer

(c) computer to card puncher and

(d) Asynchronous data method is used to transfer data from computer to printer.

Synchronous data transmission: The data transmission system in which the sending station first stores the data in the primary storage device, then divides the data into boxes and transmits one box at a time, is called synchronous transmission. Each box contains at least 80-132 characters.

Characteristics of Synchronous Data Transmission:

(i) In this transmission the sending station first stores the data in the storage device.

(ii) Data stored in the primary storage device is divided into small boxes. Each box contains at least 80-132 characters.

(iii) The time interval between every two boxes is fixed.

(iv) Each box of data has a header information at the beginning and a trailer information signal at the end.

Advantages, Disadvantages and Uses of Synchronous Data Transmission

Advantages of synchronous data transmission:

(i) Its efficiency is much higher than asynchronous.

(ii) Transmission speed is very high as transmission is continuous.

(iii) Start and Stop bits are not required at the beginning and end of each character and no time interval is required after each character.

(iv) Transmission lines are not idle. As a result the time is relatively less.

(v) Easier to identify errors in transmitted data.

(vi) This method is convenient for two-way data transmission.

(vii) This method is particularly useful for remote communication.

(ii) More data can be transmitted in less time as data is transmitted in box form.