Simplex , Half Duplex , Full Duplex Serial Communication
Simplex communication is a unidirectional communication system.
That is communication is possible in only one direction.
Typically , the transmitter sends a signal and its up to the other receiving device to figure out what was sent.
This type of communication is most efficient when there is lot of data flow in one direction , and no traffic is needed in the direction.
Broadcast system like T.V and also signals , fire alarm system etc., are good examples of simplex communication system.
In half duplex communication system , bi-directional communication is possible , but only in one direction at a time.
That means one can either transmit or receive a signal at particular instant of time in this system of communication.
One cannot transmit or receive a signal simultaneously .
Say, within a specific time interval t1 t t2 , node A is transmitting a signal to another nodes A and B will change their mode from transmitter to receiver and receiver to transmitter , respectively by switching the Duplexer.
Next , B can start sending information to A via the same link.
The Walky – talky used in defence and by police is a good example of Half duplex communication system.
In full duplex communication system simultaneous two –way communication is achieved.
Unlike half duplex communication system , one can both transmit and receive a signal simultaneously .
Telephone conversation is an appropriate example of full duplex communication system.