406 emergency beacons (ELTs registered to aircraft, EPIRBs registered to vessels, or PLBs registered to individuals) are designed to set off a needed chain of events in case of distress.
Once an alert is routed through the Cospas-Sarsat System on board NOAA and other satellites to Mission Control Centres, the local search and rescue authorities begin determining the local assistance needed, depending on the complexity of the distress.
Read an example here, based in Florida, USA:
http://sanibel-captiva-islander.com/page/content.detail/id/588730/Safe-at-Sea–EPIRB—a-sequel.html?nav=5011