Which of the following communication modes supports two-way traffic, but in only one direction at a time?

Explanation

In half-duplex, only one party transmits at a time, because both parties transmit and receive on the same frequency. Full-duplex data transmission means that data can be transmitted in both directions on a signal carrier at the same time. In simplex connection communication channel in which signals flow only outwards and cannot flow in the opposite (inwards) direction