Which statement accurately describes half duplex?

• A. Uses one frequency to transmit and receive
• B. Uses two frequencies and allows one way communication
• C. Uses two frequencies and allows simultaneous two way communication
• D. VoIP with push to talk for radios and non radio devices over IP

Answer: (B)

Half duplex means two-way communication, but not at the same time. The path is shared so a transmitter and a receiver take turns. Using two frequencies for the two directions is a common way to implement this: one frequency serves one direction and a separate frequency serves the other, and you switch who is transmitting versus who is listening. That setup makes the transmission effectively one-way at any moment, which is the hallmark of half-duplex behavior. This differs from full duplex, where both directions occur simultaneously on separate channels. Descriptions about use cases like VoIP push-to-talk describe usage, not the fundamental channel behavior, and aren’t the defining feature of half duplex.