The FD810RH-N consist of an infrared transmitter and receiver in one compact housing with reflective prisim, for expansion of the FD805R-N or FD810R-N. The FD805R-N or FD810R-N ground level controller is supplied with one detector, and can support one additional FD805RH-N or FD810RH-N unit. The infrared signal from the detector is reflected by a prism and analyzed for smoke presence. It is particularly designed to be used where point smoke detectors are not applicable due to height or inaccessibility. The FD810RH-N also features a motorized head, which allow for auto realignment in cases where gradual building shift occurs.