half duplex
Concept: Half Duplex data transmission means that data can be transmitted in both directions of a signal carrier, but cannot be transmitted at the same time. At any moment in the communication process, information can be transmitted from A to B or from B to A, but there can only be transmission in one direction. When the half-duplex mode is adopted, the transmitter and receiver at each end of the communication system are transferred to the communication line through the receiving/transmitting switch to switch directions, so a time delay will occur.
E.g:
One: Using technology with half-duplex transmission on a local area network , a workstation can send data over the line and then immediately receive data over the line from the direction the data was just transmitted. When two computers in a local area network are communicating, they can only transmit data in the same direction at the same time, because most baseband networks used in local area networks only support a single signal. In other words, the baseband network adopts the half-duplex working mode .
Two: A walkie- talkie is a half-duplex device that allows only one party to speak at the same time.
duplex
Concept: Communication allows data to be transmitted in both directions at the same time, which is equivalent in capability to the combination of two simplex communication methods. The full-duplex mode does not need to switch the direction, and the full- duplex refers to the bidirectional transmission of signals (A→B and B→A) at the same time (instantaneous). Refers to A→B at the same time B→A, is instantaneous synchronization.
For example, like we usually make a phone call, we can also hear the other party's voice while talking. Current network cards generally support full duplex.
Simplex
Concept: Data transfer is unidirectional. Among the two communication parties, one is fixed as the sender, and the other is fixed as the receiver. Information can only travel in one direction, using a single transmission line .
For example; for example the communication between the computer and the printer is simplex mode, because only the computer transmits data to the printer and there is no data transmission in the opposite direction. Also in some communication channels , such as simplex wireless transmission.