... voltage: 24V (pulse modulation) 3.Fire Alarm System Manual Call Point Addressable Fire Alarm Control System Manual Call Point AW-AMC2188 Features andTechnical parameters1 ... .1A/30VDC5. Weight: About 120g6. Wiring method: nonpolar two-bus system (L1, L2)7. Operating environment: Indoor, temperature: -10°C ... , otherwise it will be out.Matched host machine: fire alarm control panel (such as AW-AFP2188)