Abstract: A system for displaying the location of an open switch in a series alarm protection circuit containing a plurality of switches. A plurality of independent input monitoring circuits includes a display array to visually indicate the input status of each circuit, the monitoring circuits and visual displays being mounted on a common plate. The high input resistance of the monitoring circuits allows direct connection in a pre-determined sequence to the alarm protection circuit. An unconnected normally closed alarm protection loop has a higher and lower positive voltage value with respect to common voltage of the alarm unit at its input terminals. Designating the higher value as "start" and the lower value as "finish", the monitoring circuits are connected through a sequential order to the finish side of each serially connected switch. As a switch is opened all monitoring circuits that are electrically connected through a closed switch to the start terminals will display a lighted condition.