Which of the following best describes the role of a door position switch?

• A. It provides a status indication of whether the door is open or closed.
• B. It unlocks the door when activated.
• C. It records the time of door usage.
• D. It powers the door lock.

Answer: (A)

The door position switch is a sensing device that reports the door’s state—whether it is open or closed—to the control system. It provides a binary input that other building automation or safety systems use to decide what to do next, such as triggering lights, ventilation, alarms, or access control logic. It’s inherently a status indicator, not an actuator or a logger.

The other functions listed aren’t what this component does. It does not unlock the door when activated; that’s the role of the door lock or electric strike. It does not record the time of door usage; time stamping and logging require a separate event log or access control system. It does not power the door lock; power to the lock comes from the lock/actuator hardware and its power supply, while the switch simply reports position.