A fire alarm system is something that will detect fire and then to warn people of the fire.
The detection can be a person seeing the fire, a smoke detector sensing smoke, a building’s fire sprinkler system spraying water on a fire
The warning can be someone running down hallways shouting “FIRE”, a fire bell sounding, the fire horns sounding and the fire strobes flashing
The system is a mechanical or electrical means of warning everyone once a fire has been detected
CCTV (closed-circuit television) is a TV system in which signals are not publicly distributed but are monitored, primarily for surveillance and security purposes. CCTV relies on strategic placement of cameras, and observation of the camera’s input on monitors somewhere
An access control system (ACS) is a type of security that manages and controls who or what is allowed entrance to a system, environment or facility. It identifies entities that have access to a controlled device or facility based on the validity of their credentials.