Property monitoring system and method of operating. Two signal lines are used to couple a master controller in series with a plurality of indicators. Each indicator has a visual display. Each visual display has a plurality of LEDs, or other type of lighting device. The master controller is configured to generate a multi-bit digital command message to be transmitted serially to the plurality of indicators over the second signal line upon receipt of an alarm condition message. Each command message has a predetermined time delay for activating each of the indicators, or a component thereof, so that all indicators activate in unison.