Half and Full Duplex

Half Duplex:

•    It uses only one wire pair with a digital signal running in both directions on the wire.

•    It also uses the CSMA/CD protocol to help detect collisions and to permit retransmitting if a collision does occur.

•    If a hub is attached to a switch, it must operate in half-duplex mode because the end stations must be able to detect collisions.

•   Half-duplex Ethernet—typically 10BaseT—is only about 30 to 40 percent efficient because a large 10BaseT network will usually only give you 3 to 4Mbps—at most.

Full Duplex :

In a network that uses twisted-pair cabling, one pair is used to carry the transmitted signal from one node to the other node. A separate pair is used for the return or received signal. It is possible for signals to pass through both pairs simultaneously. The capability of communication in both directions at once is known as full duplex.