Final answer:
A fire alarm system is responsible for activating all audio/visual devices in a building when a fire is detected, consisting of detectors, manual pull stations, and signaling devices that warn occupants to evacuate.
Step-by-step explanation:
The feature that activates all the audio/visual devices throughout a building when a fire is detected is known as a fire alarm system. This system is designed to alert occupants of the presence of a fire, giving them time to evacuate safely.
The system typically includes components such as smoke detectors, heat detectors, manual pull stations, audible signaling devices (like horns or sirens), and visual indicators (like strobe lights). When the system senses a fire through its detection devices, it triggers the alarm to sound throughout the building, ensuring that all occupants are informed and can respond appropriately.