Which of the following is one of the three technical components of an intrusion detection system?

• A. An alarm sensor
• B. A video camera
• C. A door lock
• D. A power supply

Answer: (A)

An intrusion detection system relies on sensors to detect unauthorized entry, a central processing unit to analyze signals and decide if an alert is warranted, and an annunciation or alerting mechanism to notify security personnel. The alarm sensor is the sensing device that actually detects an intrusion event (like a door opening or motion) and triggers the system to respond. While a video camera can aid in surveillance and a door lock is an access control measure, neither is the detection element at the heart of an IDS, and a power supply, though essential, is support hardware. So the alarm sensor best fits as one of the technical components.