Homework / test English Tech/Engineering Telecom(munications) radio

Hi all,

Please explain and give equivalent term(s) for "Man Down" in the following paragraph:
Man Down
This feature allows the radio to emit a tone if it tilts a certain gradient (programmed by the dealer) or stays motionless for a certain time period (programmed by the dealer). The radio will trigger an emergency alarm automatically if you don’t make any response (e.g. position the radio upright if it tilts, or change its position if it is motionless) within the period when the tone continues. To cancel the emergency alarm, please move it or place it upright.

Thank you very much in advance