... 3. every zone could connect with 10 sensors 4. LCD display Wireless GSM Security Alarm SystemsFunction Instruction:1) Built ... Defence zones,each zone can add 10 sensors;3) LCD screen with time clock display;4) Voice prompt for ... like a telephone;13) One-key-control function: Out Arm, Home Arm, Remote Arm;14) SOS, fire, gas, door, hall, window, ... : Wireless GSM Security Home Alarm System with LCD Display