EPIRBs are tracking transmitters which aid in the detection and location of boats, aircraft, and people in distress.An Emergency Position Indicating Radio Beacon(EPIRB) is used to alert search and rescue services in case of an emergency. EPIRB does it by transmitting a coded message on 406 MHz distress frequency via satellite .
When manually activated, or automatically activated upon immersion or impact, such beacons send out a distress signal. The signals are monitored worldwide and the location of the distress is detected by non-geostationary satellites and in more recent EPIRBs also by GPS.
Emergency beacons operating on 406 MHz transmit a unique character serial number called a Hexa decimal Code. When the beacon is purchased, the Hex Code should be registered with the relevant national (or international) authority.
Registration provides Search and Rescue agencies with crucial information such as: