Alarm signal

A signal that notifies externally when an abnormal condition occurs in the main body or operating environment of electrical or electronic equipment. Examples of abnormalities in the main body include input or output anomalies. An example of an abnormal operating environment is a temperature anomaly. The purpose of the signal may be to inform people of an already occurred abnormality to take actions such as stopping the equipment, or to notify of a precursor to an abnormality to prevent failure through proper measures.