Half Duplex and Full Duplex

If communication is only possible in one direction (transmission or reception), this is called half duplex mode. However, the separate transmit and receive lines of today’s twisted pair cabling for ETHERNET networks also allow full duplex operation. In full duplex mode, the stations can simultaneously exchange data in both directions independent from each other. Due to this, the CSMA/CD method is not necessary in full duplex mode. Networks with more than two stations working in full duplex mode can only be implemented using switches because these switches establish peer-to-peer connections between the individual stations (refer to 1.4 Cabling).