Smoke detectors intercommunicate through a process known as "interlinking." This feature allows multiple smoke detectors in different areas of a dwelling or building to be interconnected, so that when one alarm is triggered, all of the other interconnected alarms will also sound.

Interlinking smoke detectors can significantly increase the safety of a building by ensuring that occupants in all areas of the structure are alerted to a fire regardless of where it starts. This is particularly important in homes or buildings with multiple floors or large floor plans, where the sound of a single alarm may not be audible in all areas.

There are two primary methods used to interlink smoke detectors: wiring and wireless connectivity.

Wired Interlinking: In wired interlinking, smoke detectors are physically connected to each other using electrical wiring. This method requires professional installation and is typically used in new construction or major renovations. Wired interlinking is reliable and provides continuous communication between detectors, but it can be more complex and costly to install than wireless interlinking.

Wireless Interlinking: In wireless interlinking, smoke detectors communicate with each other using radio signals. This method does not require physical wiring and is simpler to install, making it a popular option for existing buildings and do-it-yourself projects. Wireless interlinking relies on batteries or a separate power source for each detector, and the effectiveness of communication can be affected by factors such as the distance between detectors and the presence of interference.

When selecting and installing interconnected smoke detectors, it is important to follow the manufacturer's instructions carefully and to ensure that all detectors are compatible with each other. Additionally, it is recommended to test the interlinking feature regularly to ensure that all alarms sound when one is triggered.