DC-23-NB-LTE-M is a door contact designed to detect the unauthorized opening and closure of doors or windows. DC-23-NB-LTE-M is multi-functional, with a built-in extension terminal which allows it to be added to an existing wired sensor. DC-23-NB-LTE-M can incorporate NB-IoT / LTE-M technology and send status or alarm signals to the system server via NB-IoT / LTE-M network, offering users system deployment flexibility. Powered by a CR123 3V Lithium battery, DC-23-NB-LTE-M is particularly created to enhance operational efficiency, lower power consumption and reduce maintenance costs. Its elegant and modern design allows it to fit seamlessly into any environment.