Transmission modes is the way data flows from the source to the destination. There are three modes of data transmission. Data can be transmitted in any one of them. These are as follows:-
- Simplex Mode
- Half-Duplex Mode
- Full-Duplex Mode
Simplex Mode:- In the simplex mode of data transmission the data can be transmitted in one direction only. It means that we can either send the data or receive the data at a time. This mode of transmission is not preferred as one needs to get the response of the data transmitted. It has to be transmitted back or error signals have to be transmitted back which all require in return. This does not give a reliable output as if the data is lost, will not be able to retrieve (as no acknowledgment is given ). Pager is an example of a Simplex Mode of data transmission.
one way data flow
(SENDER) ===================> (RECEIVER)
Half-Duplex:- In the Half-Duplex mode of data transmission the data can be transmitted in either direction, but not at a given point of time. It means that we cannot have two way data transmission simultaneously. In the wireless system this mode is used only person can talk either the sender or the receiver at a time. For example, Valkietakie is the best example of the Half-Duplex as the sender and the receiver can talk only one by one.
data flow both ways but one at a time
SENDER ==========================> RECEIVER
One at a time
SENDER <========================== RECEIVER
Full-Duplex:- In Full-Duplex mode of data transmission, the data can be transmitted in both the directions at any given point of time i.e. we can have simultaneously data transmission in either direction. This is most accepted form of the transmission mode because it is faster. Time is saved as data from either direction flow at the same instance of time. It works on a telephone line on which we can talk with the other person at the same time. For example, telephone, or mobile helps in the data transfer from sender and receiver at a time.
data flow both ways simultaneously
SENDER =========================> RECEIVER
SENDER <========================= RECEIVER