The beam operates totally on the basic principle of sunshine obscuration using infrared. The OSI-RI detector is really a blended transmitter/receiver that could be instantly linked to an intelligent detector circuit in LiteSpeed® or CLIP mode. Unwanted alarms a result of the beam becoming fully obscured for a short length https://www.firesense.co.uk/type/addressable-fire-system/addressable-beam-detectors/