US Patent 7187279 Security system and a method of operating

A method of operating a security system is disclosed as including sensors for detecting occurrence of at least one security related event, e.g. motion, and alarm devices, in which the sensors and alarm devices are operatively associated with each other, e g. by being connected with each other via a digital communication backbone (124), including the steps of assigning a threat level to each security-related event; determining the current threat level of the system; comparing the current threat level of the system with a predetermined threshold threat level; causing the alarm devices to produce alarm signals when the current threat level reaches or exceeds the threshold threat level.