Listen-in monitoring relies on which component to hear inside the premises when a sensor is tripped?

• A. Speakers
• B. Microphones
• C. Cameras
• D. Motion detectors

Answer: (B)

Microphones are the component that enables listen-in monitoring because they hear inside the premises and feed that audio to the monitoring station when a sensor is tripped. A microphone converts sound into an electrical signal that can be transmitted by the system, allowing responders to verify what’s happening by listening for voices, noises, or glass breaking. The other components don’t capture audio: speakers emit sound, cameras capture video, and motion detectors detect movement. In systems with two-way audio, the microphone remains the listening input, while the speaker handles any response.