System Parameters Processor: 32-bit Storage: Storage for 3000 Legal Card Information Card Type: EM Card Device Interfaces Input Interface: Exit Button  1, Door Sensor  1 Output Interface: Doorbell  1, E-lock Output  1 General Key Board: 13 Keys (0-9, , *, #, Doorbell) Working Current: 0.17A (without Load) Working Voltage: 12V DC Prompt: Beeper LED Indicator: Power/Status Working Temperature : -20°C to +65°C (-4°F to +149°F) Working Humidity: 10% to 90% (Non-Condensing) Dimensions (LxWxH): 126.5(L)mm  94.5(W)mm  24(H)mm (4.98"  3.72"  0.94")