So that If one activates, they all go off. Early warning. If the one in the basement goes off due to fire, and both the basement door and your bedroom door on the third floor are closed, you might not hear the alarm until it's too late. If the basement activates the entire house, you should hear it even if the doors are closed.
answered 5 months, 2 weeks ago
I our double wide home there are several smoke detectors. The are all wired for electric & batteries for extra protection.