The Thorn Security 811PH is an intelligent, addressable multi-sensor detector that combines advanced optical smoke sensing with thermal (heat) detection. Designed for use with Tyco MX technology fire alarm systems, it provides a fast and reliable response to a wide range of fire types. By correlating signals from both the smoke and heat sensors, the 811PH offers enhanced detection performance and a high degree of immunity to false alarms, making it an ideal choice for demanding environments like hotels, hospitals, and commercial properties.