Full-duplex and Half-duplex

In network communication we may have heard about duplex,simplex,half-duplex,full-duplex so i’m gonna talk about that things

  • term duplex means how networking devices can communicate to each other, (how devices can transmit data and receive)

  • Full Duplex

In full duplex transmission mode, the communication between sender and receiver can occur simultaneously. The sender and receiver can both transmit data and receive at the same time

Telephones are full-duplex systems so both parties on the phone can talk and listen at the same time

  • Half Duplex

in Half Duplex both side can communicate but not at the same time, for example if computer A sending data to Computer B, then computer B have to wait until receive data to start sending back.

Walkie-talkie radio communication is a half-duplex system

HUB is also Half-Duplex because hub sends data to broadcast
For example, if Computer A sending data, data must go to every network devices, and if data transfering moment, Computer B decides to send data, it’s going to happen Collision ,
Collision is when in Half-duplex communication two side decides to transfer data at same time, in that moment data will be lost, and devices have to send it again (in a row)



  • Simplex

In simplex transmission mode, the communication between sender and receiver occurs in only one direction. The sender can only send the data, and the receiver can only receive the data. The receiver cannot reply to the sender.

Simplex transmission can be thought of as a one-way road in which the traffic travels only in one direction—no vehicle coming from the opposite direction is allowed to drive through.

To take a keyboard / monitor relationship as an example, the keyboard can only send the input to the monitor, and the monitor can only receive the input and display it on the screen. The monitor cannot reply, or send any feedback, to the keyboard.


Networking is a less known field among security professionals. Articles like these which explain fundamental terms and concepts of networking will help tremendously. I hope this series continue :slight_smile:


I’m very happy that people liked this topic, definitely i’ll continue posting… :smiling_face_with_three_hearts: :cowboy_hat_face: