The beam operates primarily on the principle of sunshine obscuration applying infrared. The OSI-RI detector is often a merged transmitter/receiver which can be immediately connected to an clever detector circuit in LiteSpeed® or CLIP manner. Undesired alarms due to the beam getting fully obscured for a short time frame is https://www.firesense.co.uk/type/addressable-fire-system/addressable-beam-detectors/