The AD365/-IV and AD365A/-IV are plug-in addressable multi-criteria detectors that replace the AD355 Series. They combine photoelectric, thermal, and infrared (PTIR) sensors in one unit to sense multiple components of a fire. This approach enables enhanced sensitivity to real fire with heightened immunity to nuisance particulates. Multiple sensors and communication can greatly reduce nuisance alarms compared to single sensing methods. Sophisticated algorithms maximize the advantages of the sensor types. This detection strategy offers heightened immunity to nuisance particulates and enhanced sensitivity to real fire.