Which of the following conditions must be supervised on a voice communication speaker circuit?

Question: Which of the following conditions must be supervised on a voice communication speaker circuit?

Answer options:

• Ground fault in the AC circuit ✅ An open circuit on the speaker loop
• The microphone is unplugged
• The volume is turned down to 50%

Correct answer: An open circuit on the speaker loop

Explanation: S524 requires that if the voice system fails, it must be capable of automatically reverting to a standard alarm tone (like temporal 3) if possible, but specifically, the amplifiers must be supervised.