When activated, all smoke detectors in your home alarm at the same time. Tricky-wired detectors are often on and when the facility goes out, the battery backup kicks in.????? ????? ??????? ?????????? ????? ??? ?? ??? ????? ????? ????? ?? ??????? ??????? ??? ?????? ?...???? ???????? ???? ??? ???? ???? ???????? ???? ??? ???? ?????? ????? ?? ???????..