• PIEPS DSP PRO (Version v1.4/January 2014)
  • PIEPS DSP PRO ICE (Version v3.0/October 2015)
  • PIEPS DSP SPORT (Version v3.0/October 2015)



"Auto-Revert Search-to-Send“, hereinafter reffered to as „AR“, is an additional function in avalanche beacons with the following goal: Getting caught and buried by an avalanche with a beacon in SEARCH mode, the AR function provides automatically switching from SEARCH to SEND.


Originally only time controlled, the technical implementation is now time and movement controlled in modern avalanche transceivers. That means that the switching s performed after a defined time unless the Pieps is without movement.


The automatic switching is announced by a more or less significant warning. In this period, the switch can be manually aborted either by an active keystroke or conscious transceiver movement to maintain the SEARCH mode.



During activation of AR on your PIEPS DSP PRO / PIEPS DSP PRO ICE / PIEPS DSP SPORT, it is displayed in SEND-Mode. The signals "SEND" and "AR" are rotating. 



Die AR-Funktion wird nicht ausgelöst, solange Sie sich mit Ihrem PIEPS DSP PRO / PIEPS DSP PRO ICE in Bewegung befinden.


Die AR-Funktion wird beim PIEPS DSP SPORT nach 3:30 Minuten ausgelöst. Eine Ausnahme tritt ein, wenn Sie sich bereits in der Feinsuche zu einem Sender, also im Nahbereich < 6m, befinden. Das PIEPS DSP SPORT erkennt die Situation – die AR-Funktion wird hier nicht ausgelöst.  


Während der Warnphase kann die AR-Initialisierung manuell wie folgt unterbrochen werden:

PIEPS DSP PRO / PIEPS DSP PRO ICE: durch kurzes Schütteln des Gerätes oder durch Drücken der Taste MARK
DSP SPORT: durch Drücken der Taste MARK

Nach dem Umschalten kann der AR-SEND-Modus nicht mehr manuell unterbrochen werden – Ihr PIEPS DSP PRO / PIEPS DSP PRO ICE / PIEPS DSP SPORT sendet dann permanent inklusive Warnton bis es entweder ausgeschaltet wird (OFF) oder manuell auf SEND geschalten wird.


Basically, the AR function serves professional rescuers who have to take an increased risk at avalanche rescue operations. Not always the operation area can be evaluated as safe when nearby slopes are unloaded or the current avalanche slope is again filled with snow and is to be expected with any "secondary avalanche".

The AR function can help in the rarely occurring case of a "secondary avalanche" to save lives, but significantly often leads to major problems in search operations (training or emergency):.

  • AR is useless, if the transceiver gets lost during the accident – it starts transmitting far away from the buried victim! Avalanche transceiver safety cords have to support not more than 5kg according to the standard.
  • Long delay times!  Rescuers who stayed outside of the avalanche have to wait up to 8min (!), depending on transceiver type and setting, until the victim´s AR function initializes SEND mode.
  • Suddenly occurring, misleading transmit signals on the avalanche field are unfortunately the rule! Also transceivers with movement controlled AR function start transmitting once they´re without movement (e.g. laid apart by accident).
  • Confusion caused by AR warn signal! Specific training with exactly this situation is necessary to be able to interpret the warning correctly and to ensure effective acting.
  • Incorrect or not noticing the AR warn signal! For example caused by lack of familiarity with the function or just by loud background noise as helicopter rotors


By providing „Auto-Revert Search-to-Send“ for the PIEPS DSP PRO, PIEPS  has responded to the problems described above and now offers an AR function that is different from all others: long warn period and short delay time.

Based on these reasons the PIEPS DSP (2003-2013) never got equipped with an AR function, even it would have been easy by a firmware update. Instead, PIEPS looked for a 100% solution and finally developed the PIEPS BACKUP mini transmitter, which meets all requirements of a backup function. Professional organizations as the ÖAMTC Helicopter Rescue (Austria) or the REGA Helicopter Rescue in Zermatt (Switzerland) are equipped with the PIEPS BACKUP and they have the AR function disabled on their transceivers!

However, PIEPS wants to specifically point out, that any Auto-Revert function Search-to-Send only provides limited protection in case of a “secondary avalanche”! Complete protection is only guaranteed by using the PIEPS BACKUP.


The BACKUP transmitter is a fundamental part the personal protection equipment for each rescuer! It is fixed to the rescuer´s body independent from the transceiver. Basically, on arrival at the operation location the situation is not all clear, and by using the BACKUP transmitter the search for victims is not disturbed by switched-on, active transmitters (the BACKUP is turned on but in standby mode). Currently, the combination of the BACKUP transmitter + a modern avalanche transceiver is the only professional solution.  Using a transceiver with integrated AR is an alternative but is, however, not to be recommended as a 100% solution. Only a transmitter on the rescuer´s body is a reliable transmitter!


Cit.: Helmut Mittermayr, ÖAMTC Rescue Helicopter Crew Member & Emergency Paramedic, UIAGM Mountain Guide, Member of Austrian Mountain Guides Education Instructor Team