non polar two wire bus

90dB alarm volume direct from Wanlin Fire Protection — 12-year factory experience, WL-SFP800 smart fire detector certified UL 217/UL 268/UL 2034/UL 864/CE/EN14604/EN54/FCC. Key specs: Photoelectric Smoke Sensing + RF Wireless Interconnect (433MHz/868MHz) + Mesh Network + Self-Healing Topology, RF Wireless Mesh + 4G LTE Cat.1 Gateway + Cloud Platform + SMS/P···