1.Connection Types
In telecommunications systems the transmission of information may be
unidirectional or bidirectional. The unidirectional systems that transmit in one
direction only are called simplex, and the bidirectional systems that are able to
transmit in both directions are called duplex systems. We can implement
bidirectional information transfer with half- or full-duplex transmission
1.2 Simplex Connection
In simplex operation the signal is transmitted in one direction only. An example of this principle is broadcast television, where TV signals are sent from a transmitter to TV sets only and not in the other direction. Another example is a paging system that allows a user to receive only alphanumerical messages.
1.2.2 Duplex Connection
1.2.1 Half Duplex
In half-duplex operation the signal is transmitted in both directions but only in one
direction at a time. An example of this is a mobile radio system where the person
speaking must indicate by saying the word over that she is done transmitting and
the other person is allowed to transmit. LANs use a high-speed, half-duplex
transmission over the cable even though users may feel that the communication
is continuously bidirectional, that is, full duplex.
1.2.2 Full Duplex
In full-duplex operation signals are transmitted in both directions at the same
time. An example of this is an ordinary telephone conversation where it is
possible for both people to speak simultaneously. Most modern
telecommunications systems use the full-duplex principle, which we call duplex
operation for short.
In telecommunications systems the transmission of information may be
unidirectional or bidirectional. The unidirectional systems that transmit in one
direction only are called simplex, and the bidirectional systems that are able to
transmit in both directions are called duplex systems. We can implement
bidirectional information transfer with half- or full-duplex transmission
1.2 Simplex Connection
In simplex operation the signal is transmitted in one direction only. An example of this principle is broadcast television, where TV signals are sent from a transmitter to TV sets only and not in the other direction. Another example is a paging system that allows a user to receive only alphanumerical messages.
1.2.2 Duplex Connection 1.2.1 Half Duplex
In half-duplex operation the signal is transmitted in both directions but only in one
direction at a time. An example of this is a mobile radio system where the person
speaking must indicate by saying the word over that she is done transmitting and
the other person is allowed to transmit. LANs use a high-speed, half-duplex
transmission over the cable even though users may feel that the communication
is continuously bidirectional, that is, full duplex.
1.2.2 Full Duplex
In full-duplex operation signals are transmitted in both directions at the same
time. An example of this is an ordinary telephone conversation where it is
possible for both people to speak simultaneously. Most modern
telecommunications systems use the full-duplex principle, which we call duplex
operation for short.
