Half-duplex refers to a communication system where data or signals can only travel in one direction at a time. In a half-duplex system, one device can either send or receive information, but not both simultaneously. This means that the communication flow alternates between sending and receiving, with each device taking turns. A common example of half-duplex communication is a walkie-talkie, where one person speaks while the other listens, but they must switch roles when it's time to respond. Unlike full-duplex systems, which allow simultaneous two-way communication, half-duplex systems are more limited in terms of speed and efficiency. [ChatGPT.com (2024)]