When brought on, all smoke detectors in your house alarm at the same time. Challenging-wired detectors are generally on and when the power goes out, the battery backup kicks in.????? ????? ???? ????? ????? ????? ??? ???? ????? ?????????????? ?????? ??????? ?????? ??????? ???????? ??? ????? ?????????.??? ???? ?? ???? ????? ?? ????? ?? ???????? ??? ?