Which statement describes half-duplex transmission?

• A. Two ways at any time
• B. One way only
• C. Two way, but only one at a time
• D. All signals are simultaneous

Answer: (C)

Half-duplex transmission is a bidirectional channel that can carry data in both directions, but not at the same time. At any moment, only one side can transmit while the other receives; once done, they switch roles. This is like a walkie-talkie, where you press to talk and release to listen. This differs from simplex, which is one-way only, and from full-duplex, where both directions occur simultaneously. The statement three describes exactly this: two-way communication with only one direction active at a time.