The system includes the SC821 control panel, SM801 door/window detector, SP801 PIR detector and SR801 remote control. Up to 60 wireless devices can be connected to the SC821 control panel, supporting 12 wireless zones and four wired zones. It has a built-in 868/923MHz transceiver module with an excellent operation range of up to 250 m. The auto binding function is simple for the installation. It features a voice dialer and digital dialer, 110 dB alarm sound and stop level ??able LED and 2.5-inch LCD display. It is expandable with all Everspring U-NET Series products.