Conventional fire alarm systems smoke detector sensor with self-check function

Conventional fire alarm systems smoke detector sensor with self-check function Feature: self-check button:could self-check circuit and all components works normally or not.(also alarm if labyrinth not install well) exact smoke concentration & alarm consistency : All detector will calibrating consistency, make sure no fake alarm with less or too much smoke. could load the strong electricity:have contact output function. The 4 wires could alarm and connect 220V or 9-35V sounder