Patent ID: 8816843

Claim:
An alarm system including: one or a plurality of alarm circuits, each having a normally closed, switch position; a control circuit to which one or a plurality of the alarm circuits is/are connected, the control circuit being adapted: to apply a voltage to create a non-activation situation when the switch is closed; and remove the voltage to create an activation situation when the or one of the alarm circuits is open and means for detecting a fault in an alarm circuit, the control circuit being adapted to remove the voltage to create an activation situation when a fault is detected, wherein the means for detecting the fault includes: one or a plurality of alarm circuits including a respective series connected resistance at its switch to present the resistance to the control circuit when the switch is closed and the control circuit is further adapted to: detect the resistance of one or a plurality of alarm circuits and apply the voltage to create a non-activation situation when the resistance is detected in the one or a plurality of the alarm circuits, indicating switch closure, and apply no voltage not only when one or a plurality of the alarm circuits is open circuit but also when the resistance is not detected.