Fire alarm certification independent gas alarm fire certification joint linkage gas alarm (excluding solenoid valve) fire certification joint linkage gas alarm + solenoid valve (signal line standard line) fire certification joint gas alarm + solenoid valve (signal line lengthening Line) intelligent voice models independent gas alarm intelligent voice fire certification joint linkage alarm (excluding solenoid valve) intelligent voice fire certification joint linkage alarm + solenoid valve (signal line standard line) intelligent voice fire certification linkage alarm + electromagnetic Valve (signal line extension line)