Which type of surveillance sensor is commonly used to detect door and window status?

Which type of surveillance sensor is commonly used to detect door and window status?

• A. CCTV cameras
• B. Door/window sensors
• C. Fire alarms
• D. Access control readers

Answer: (B)

Door/window status is best monitored with door/window sensors, also called contact sensors. These devices use a magnet on the door or window and a sensing element on the frame. When the door or window is closed, the magnet keeps the circuit closed; if it opens, the circuit is broken and the security system is alerted. This provides immediate, reliable status of perimeter entries and is inexpensive to deploy, making it a common choice for detecting whether doors or windows are open or closed. CCTV cameras, by contrast, are for visual surveillance and evidence rather than live status of open/closed, fire alarms monitor heat or smoke, and access control readers manage entry permissions rather than continuously reporting the physical state of each door or window.

Door/window status is best monitored with door/window sensors, also called contact sensors. These devices use a magnet on the door or window and a sensing element on the frame. When the door or window is closed, the magnet keeps the circuit closed; if it opens, the circuit is broken and the security system is alerted. This provides immediate, reliable status of perimeter entries and is inexpensive to deploy, making it a common choice for detecting whether doors or windows are open or closed.

CCTV cameras, by contrast, are for visual surveillance and evidence rather than live status of open/closed, fire alarms monitor heat or smoke, and access control readers manage entry permissions rather than continuously reporting the physical state of each door or window.