refers to bi-directional communications. “Full” duplex describes bi-directional communications all the time. Regular communications between individuals conversing face-to-face is full-duplex. In other words, you can talk and listen simultaneously. Full-duplex communication allows simultaneous two-way conversations – one person can interrupt another. “Half” duplex allows two-way conversations, one way at a time – one person can NOT interrupt another. Half-duplex is where a user can only talk (transmit) or listen (receive) on their device at any moment and for wireless systems only one user can be transmitting on a frequency at any moment.