Intrusion Detection Systems Flashcards

What is the purpose of 'alarm verification' in a modern intrusion detection system, and how does it reduce law enforcement response burden?

Answer: It uses video, audio, or sequential sensor activation to confirm an intrusion before dispatching authorities, reducing false alarms

Alarm verification (using video clips, audio, or two-sensor activation) reduces false dispatches — which constitute 94-98% of US police alarm responses — improving response efficiency and reducing fees.

What does 'Grade' mean in the context of EN 50131 intrusion detection system standards used as reference in US security specifications?

Answer: The risk level classification (1-4) that determines required system performance and tamper resistance

EN 50131 Grades 1-4 define increasing levels of risk and required system performance: Grade 1 for low risk, Grade 4 for high risk requiring the highest tamper resistance and redundancy.

A passive infrared (PIR) detector is installed near an exterior glass wall. What is the MOST likely source of false alarms in this installation?

Answer: Direct sunlight or headlights shining through the glass, causing rapid temperature changes in the detection zone

PIR detectors sense changes in infrared (heat) energy — sunlight or vehicle headlights shining through glass can rapidly heat objects in the detection zone, mimicking a human body and triggering false alarms.

In alarm system design, what is the 'defense in depth' approach to intrusion detection?

Answer: Installing multiple sensor types and layers so that an intruder must defeat several independent systems to reach the target undetected

Defense in depth layers perimeter, exterior, interior, and point protection so that bypassing one detection layer still leaves additional layers that must be defeated, increasing detection probability.

What alarm transmission technology offers the MOST reliable path from premises to monitoring center against communication sabotage?

Answer: Dual-path: cellular + broadband IP with automatic failover

Dual-path communication using both cellular and broadband IP with automatic failover is most resistant to sabotage because cutting one path (phone/cable line) still leaves the cellular path active.

According to ASIS guidelines, how long should alarm event logs be retained for commercial and industrial facilities?

Answer: 1 year minimum

ASIS recommends retaining alarm event logs for a minimum of 1 year to support investigations, legal proceedings, and trend analysis of alarm patterns.