alarm signal

A signal that notifies externally when an abnormal condition occurs in the main unit or usage environment of electrical or electronic equipment. Examples of abnormalities in the unit include input and output errors. Examples of environmental abnormalities include temperature anomalies. The purpose of the signal is either to notify humans after an abnormality has occurred so that measures like stopping the equipment can be taken, or to alert them to signs of an abnormality in advance to prevent failure through proper action.