The OSI-RI-SK is a intelligent addressable reflector-type linear optical beam smoke detector. It is uniquely suited for protecting large open areas with high ceilings, where spot-type smoke detectors are difficult to install and maintain. Ideal applications include warehouses, atriums, aircraft hangers, sporting arenas and concert halls. The beam operates primarily on the principle of light obscuration using infrared. The OSI-RI-SK detector is a combined transmitter/ receiver that can be directly connected to an intelligent detector circuit and is compatible with Silent Knight Addressable Fire Alarm Control Panels.