When using multiple interconnected smoke alarms, how do they respond to smoke?

When multiple interconnected smoke alarms are used in a system, the key feature is that the action of one alarm detecting smoke activates the others in the network. This interconnected system is designed to enhance safety by ensuring that when one alarm goes off due to smoke, all alarms will sound, providing a comprehensive alert throughout the entire area or home. This mutual activation is crucial in larger spaces or multi-level homes where one may not be able to hear an isolated alarm in another part of the building.

The other options describe features of smoke alarms but do not address how they function when interconnected. Battery backup ensures that alarms can operate during a power outage, hard wiring ensures a constant power supply from the electrical system, and the suggestion that they should not be interconnected contradicts the safety benefits provided by such a system. The interconnected design is a critical aspect of modern smoke alarm systems, providing a significant increase in alertness and safety for occupants.