... wireless defense zones 3. every zone could connect with 10 sensors 4. LCD display Wireless GSM Security Alarm Systems Function Instruction:1) Built ... add 10 sensors;3) LCD screen with time clock display;4) Voice prompt for all operations;5) Remote control home appliances function (Option);6 ... like a telephone;13) One-key-control function: Out Arm, Home Arm, Remote Arm;14) SOS, fire, gas, door, hall, ...