Functions and features: 1 Offer 4 / 8 RJ11 output ports to connect 4 / 8 sensors or display systems. 2 Offer 1 external remote RJ12 port to connect various external alarm signal / siren such as ES521IR to realize long-distance remote function. 3 Simple and small appearance design, output port in 2 sides is convenient, LED indication function to show work condition of every defense area. 4 Built-in rechargeable lithium battery with 7 days standby time in maximum, low battery indication function. 5 Alarm will be triggered when alarm unit is detached. 6 Code modification function. 7 Offer power switch. 8 Built-in short-circuit protection function. Main parameters: 1 Size: 120 X 60 X 22mm. 2 Case: ABS. 3 Output port: 4 / 8 ports of RJ11. 4 Alarm volume: â?¥100DB. 5 Standby time of built-in rechargeable lithium battery: 7 days. 6 Code modification function: yes. 7 Low battery indication: yes. 8 External power on / off indication: yes. 9 Power input port: DC. Optional accessories: 1 Power adapter: 5V/8A. 2 AS3X series IR remote keys. 3 ES521IR external remote signal. For more functions and accessories, kindly please contact our sales or local distributor.