47 defense zones study codes security alarm dial system: 1.Siren / mute siren and continue dial your pre-set 4 groups of Tel No. at first time when an accident(theft,gas leakage, smoke accumulation danger ect) happen. 2.Call first your preset tel, even another call already coming . 3.Faraway control by telephone under password protection to operate the system such as arm, disarm, activate siren, shut siren, hear what happen ect. 4.Can work with gas leakage alarm, smoke alarm, PIR detector , wireless door/window detector, emergent button, wireless controller, ect. 5.Study code function makes it extreme easy to work with other accessory detectors . 6.With UPS power supply or rechargeable battery support , make it work for 48 hours under the situation of no electricity . 7.With 47 defense zones, wide and strong protection .