Intrusion Detection Systems Flashcards

What is the primary difference between a 'point' intrusion detection sensor and a 'line' or 'volumetric' sensor?

Answer: Point sensors protect a single specific location (door/window), while volumetric sensors cover an entire area or zone

Point sensors (magnetic door contacts, glass break detectors) protect a single discrete location, while volumetric sensors (PIR, microwave) detect intrusion throughout an entire protected volume or zone.

Which type of motion detector is MOST resistant to false alarms caused by HVAC air currents, heat vents, and changes in ambient temperature?

Answer: Dual-technology (PIR + microwave) detector

Dual-technology detectors require BOTH PIR and microwave to simultaneously trigger before generating an alarm, dramatically reducing false alarms caused by environmental factors that typically affect only one technology.

In an alarm system, what does a 'supervisory circuit' monitor?

Answer: The integrity of wiring and sensors to detect tampering or sabotage

Supervisory circuits use end-of-line resistors or active monitoring to continuously verify sensor wiring integrity, generating an alarm if wires are cut, shorted, or tampered with.

Under UL 2050 standards for central station alarm monitoring, what is the maximum response time for a central station to call the subscriber after receiving an intrusion alarm signal?

Answer: 90 seconds

UL 2050 requires central stations to attempt to contact the subscriber within 90 seconds of receiving an intrusion alarm signal to verify the event.

What is a 'shunt' in the context of an intrusion detection system, and when is it used?

Answer: A bypass of a specific sensor zone to allow legitimate access without triggering an alarm

Shunting bypasses a specific sensor zone (such as a door used for deliveries) so that access can occur without triggering an alarm, while the rest of the system remains armed.

Which IDS sensor is specifically designed to detect an attempt to break through walls, floors, or ceilings rather than entering through doors or windows?

Answer: Seismic/vibration sensor

Seismic/vibration sensors detect the physical vibrations caused by drilling, sawing, or hammering through walls and structural elements, providing 'structural penetration' detection.