Which type of communication occurs in one direction only?

Simplex communication is characterized by the transmission of data in one direction only. In this method, information flows exclusively from the sender to the receiver without allowing any return communication from the receiver back to the sender. This is unlike other forms of communication.

For example, a good illustration of simplex communication is a television broadcast where the signal is sent from the broadcaster to the viewer, but the viewer cannot send any signals back to the broadcaster. This one-way communication is straightforward and efficient for scenarios where feedback is not required.

Full duplex communication allows for simultaneous two-way communication, enabling both parties to send and receive messages at the same time. Half duplex permits two-way communication but only one party can transmit at a time. Bidirectional communication generally refers to systems that support two-way communication but doesn't specify the directionality as clearly as simplex does.

Understanding these distinctions clarifies why simplex is defined as one-directional: it exclusively conveys data from a source to a destination without the possibility of return signals.