... dual network of GSM + telephone cable, the System is more secure and reliable. 2.With the quad-band GSM module for ... , Door Lock, Living Room, Window, Balcony, and Perimeter Alarm. 17.Includes multiple zone programming functions like Real-Time, Delay ... (frequency range 20-1000 MHZ) GSM Frequency: 900 / 1800MHz dual-band automatic switch External alarm horn sound intensity: 110db Working environment ...