Product Features： 1.Built-in standalone CPU, quick calculating speed and excellent stability. 2.Non-polarity two-wire bus to make cabling easy, and avoid wrong wirin. 3.Sealed robber type of heat sensitivity component enhances anti-humidity and anti-erosion. 4.Three sensitivity levels of the detector are optional at the control panel to suit different environments. 5.Temperature rising compensation to improve responsive capacity upon different temperature rising status. 6.Special production process to make the device work at high temperature,high humidity and high altitude environment. 7.ESD static protection grade 12000V, strong anti-interference ability.