polarity insensitive connection

high sensitivity detection direct from Wanlin Fire Protection — 12-year factory experience, WL-SFP700 smart fire detector certified CE/EN14604/EN54/UL217/UL268/FCC. Key specs: ARM Cortex-A7 Processor + 4G LTE Cat.1 + WiFi + Ethernet + Zigbee + Bluetooth + Cloud Platform Integration, 4G LTE Cat.1 + WiFi + Ethernet + Zigbee + Bluetooth + IoT Cloud Platform + A···