Like all Signature Optica Series detectors, the SIGA-OSHCD is an intelligent device that gathers analog information from multiple optical sensors, converting this data into digital signals. Utilizing dual optical wavelengths combined with multiple detection angles, the SIGA-OSHCD differentiates particles that are not representative of actual smoke. Particle data is input into digital filters which feed a series of ratios removing signal patterns that are typical of nuisance sources, thus reducing unwanted alarms. To make an alarm decision, the detector’s on-board microprocessor measures and analyzes all optical sensor readings and compares this information to preprogrammed settings. The detector also analyzes the smoke and heat sensors independently from the CO sensor to determine whether to initiate a fire alarm, a life safety CO alarm, or both.