The beam operates totally on the theory of light obscuration utilizing infrared. The OSI-RI detector is usually a merged transmitter/receiver which can be straight linked to an smart detector circuit in LiteSpeed® or CLIP mode. Undesired alarms mainly because of the beam getting fully obscured for a short time frame https://www.firesense.co.uk/type/addressable-fire-system/addressable-beam-detectors/