The beam operates primarily on the basic principle of sunshine obscuration employing infrared. The OSI-RI detector can be a blended transmitter/receiver that may be straight linked to an clever detector circuit in LiteSpeed® or CLIP method. Undesired alarms mainly because of the beam remaining totally obscured for a short period https://www.firesense.co.uk/type/addressable-fire-system/addressable-beam-detectors/