Which of these is NOT a function of a smoke detector?

A smoke detector is specifically designed to detect smoke as an indicator of fire and to alert occupants of the presence of smoke, thereby providing critical early warning of potential fire hazards. Its primary functions include detecting fire, alerting individuals in the vicinity, and contributing to a fire safety plan by providing an early warning to facilitate evacuation or response.

Acting as a security system is outside the intended use of a smoke detector. A smoke detector's technology is not suited for monitoring security threats such as unauthorized entry or burglary, which require different systems, such as burglar alarms or surveillance cameras. Thus, identifying that acting as a security system is not a function of a smoke detector reinforces the understanding of its specific role in fire safety.