7 Difference Between Simplex, Half Duplex And Full Duplex Modes Of Data Transmission

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Transmission mode refers to the mechanism of transferring data between two devices connected over a network. There are three types of transmission modes, they include:

  • Simplex Mode
  • Half duplex Mode
  • Full duplex Mode

In simplex mode, communication flows in one direction (unidirectional). A device can only send the data but cannot receive it or it can receive the data but cannot send the data. Examples of simplex mode are loudspeakers, television broadcasting, television and remote, keyboard and monitor etc.

Full-duplex (FDX) and half duplex (HDX) are two types of duplex communication system. A duplex communication system is a point to point system composed of two or more connected parties or devices that communicate with one another in both directions. Duplex systems are employed in many communication networks, either to allow for simultaneous communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field. 

In a full duplex system, both parties communicate with each other simultaneously.  An example of a full duplex device is a telephone, in which case the parties at both ends of a call can speak and be heard by other party simultaneously.

Half-duplex (HDX) system provides communication in both directions but only one direction at a time (not simultaneously). Typically, once a party begins receiving a signal, it must wait for the transmitter to stop transmitting, before replying. An example of a half duplex device is a walkie-talkie. In a walkie-talkie, one must use ‘’over’’ or another previously designated keyword to indicate the end of transmission and ensure that only one party transmits at a time, because both parties transmit and receive on the same frequency.

What You Need To Know About Simplex

  1. In simplex mode of transmission, one station is the transmitter and the other is the receiver. Here, information is one way, that is, it is only the transmitter that sends data or information.
  2. This type of communication can be referred to as uni-direction.
  3. Examples of simplex mode are Keyboard, Mouse and monitor, radio broadcasts, Television.
  4. There is no mechanism in which the information can be transmitted back from receiver to sender.
  5. The entire capacity of the channel is used to send data in one direction. Therefore it is used when maximum bandwidth is required during the transmission. 
  6. Simplex yields significantly low performance than half duplex and full duplex.
  7. With simplex, there is maximum utilization of bandwidth.

What You Need To Know About Half Duplex (HDX)

  1. In half duplex transmission mode, two systems are connected by a point to point link to transmit and receive signal. Both ends can transmit but one at a time.
  2. This type of communication can be referred to as Bi-directional.
  3. Example of half duplex mode is walkie-talkie set.
  4. Sender can send as well as receive data (but one at a time).
  5. It is used to conserve bandwidth as only a single communication channel is required, which is shared alternatively between the two directions.
  6. Half duplex mode yields a better performance when compared to simplex.
  7. With half duplex, there is less utilization of bandwidth during transmission. 

What You Need To Know About Full Duplex (FDX)

  1. In full duplex mode of transmission, signals are transmitted in both directions; both end stations can receive and send data at the same time. Full duplex mode requires two independent channels, one for receiving the data and other for transmitting the data.
  2. This type of communication can be referred to as Bi-directional.
  3. Example of half duplex mode is mobile telephony.
  4. Sender can send and receive data (both simultaneously).
  5. It is used when communication in both directions is required all the time without any delays.
  6. Full duplex has by far a better performance when compared to both simplex and half duplex.
  7. With full duplex, bandwidth utilization is doubled.

Also Read: Difference Between Synchronous And Asynchronous Transmission

Between Simplex, Half Duplex And Full Duplex In Tabular Form

BASIS OF COMPARISON SIMPLEX HALF-DUPLEX FULL-DUPLEX
Description In simplex mode of transmission, one station is the transmitter and the other is the receiver. In half duplex transmission mode, two systems are connected by a point to point link to transmit and receive signal. In full duplex mode of transmission, signals are transmitted in both directions; both end stations can receive and send data at the same time.
Alternative Name This type of communication can be referred to as uni-direction.   This type of communication can be referred to as Bi-directional.   This type of communication can be referred to as Bi-directional.  
Examples Examples of simplex mode are Keyboard, Mouse and monitor, radio broadcasts, Television.   Example of half duplex mode is walkie-talkie set.   Example of half duplex mode is mobile telephony.  
Sender There is no mechanism in which the information can be transmitted back from receiver to sender.   Sender can send as well as receive data (but one at a time).   Sender can send and receive data (both simultaneously).  
Use The entire capacity of the channel is used to send data in one direction. Therefore it is used when maximum bandwidth is required during the transmission.    It is used to conserve bandwidth as only a single communication channel is required, which is shared alternatively between the two directions.   It is used when communication in both directions is required all the time without any delays.  
Performance Simplex yields significantly low performance than half duplex and full duplex.   Half duplex mode yields a better performance when compared to simplex.   Full duplex has by far a better performance when compared to both simplex and half duplex.  
Bandwidth Utilization With simplex, there is maximum utilization of bandwidth.   With half duplex, there is less utilization of bandwidth during transmission.    With full duplex, bandwidth utilization is doubled.