An Emergency Beacon is a sophisticated long-range combination communicator and signal transponder. The Emergency Beacon's internal transponder monitors common emergency search–and–rescue channels (one at a time). When traffic is picked up, the device simultaneously emits a shrill warning tone to alert users to the possibility that help is at hand and transmits a coded distress signal. When transmitting an emergency signal it is an Active device. Some more expensive models have provision for a taped, auto-repeat distress call, instead of the automatic code signal.
The Emergency Beacon serves as a means of establishing contact when there is any search being mounted within 500 kilometers, and then it serves to continue communications after that initial contact. The transponder operates for 30 days.