An alarm or intrusion monitoring system includes a plurality of detectors which communicate with a displaced control element. Various of the detectors include local storage circuitry wherein detected conditions or events are recorded along with a time indicator. Recorded events and respective times of occurrence can be downloaded to the control element for evaluation. Detected conditions or events can include system conditions, such as faults or detector off-line indicators, as well as various intrusion or environmental-type incidents such as smoke, gas, temperature or fire.