The R-855UM radio was introduced in the Soviet Air Force and many Warsaw Pact air forces at the turn of the 1960s and 1970s. The Soviet experts examined the captured US-made examples of survival radios and designed their own, all-solid state model. The R-855UM operated on a single x-tal controlled channel in the VHF airband spectrum, usually 121.5 MHz,
however there were other crystals available. It could provide AM voice communications and MCW distress signal. Transmitter power was to be no less than 0.13 Watt, the receiver comprised a super heterodyne circuitry. During voice communications, the set should provide up to 60 hrs work (1:3 tx/rx ratio), while in the beacon mode, the battery lasted for 24 hours.

The R-855UM set comprised of two units: the TRx and the battery  connected with a cable. The transmitter (nomenclature JaJe 5.000.065) weighted 0.4 kg and measured 130x68x30 mm. It was equipped with the Tx and Rx buttons, mode switch, microphone, speaker and connectors for battery and antenna. The Hg-Zn battery named Priboy-2S weighted 0.5 kg and measured 136x80x25 mm and was to be held in a survival vest or flight suit's pocket. The set could also be worn inside a pouch with a strap around the operator's neck. 

There were two antenna types for this radio available: a whip, which provided up to 56 km communications range with a SAR aircraft flying at 3000 meters, or a Komar-2M antenna (Kulikov type) with an inflatable bladder to allow floating, which allowed up to 64 km communications range. The Komar-2M antenna could break under some circumstances and the rings could be lost. Its sharp end could also damage the airman's life raft when person was trying to get inside, as it happened to a Polish AF pilot when he ejected over Baltic Sea in the 1980s. Therefore, the whip antenna was preferred. 

The R-855UM set could be used for ground to air SAR communications and LOS ground communications with up to 1-km range between the two sets. During a SAR mode, it could be used for voice communications using its internal microphone and speaker or using the aircrew headsets' or helmets' audio accessories. The flight helmet's plug was connected to an auxiliary socket on the cable linking the Priboy battery with the transceiver unit. The following helmets could be used with the appropriate cable: GSh-6A, GPSh-3, ZSh-3M and GSh-8A. 

During the 1990s many R-855UM's remained in service with the Russian and the former Soviet Block air forces. Since the set is much outdated, obsolete and not suitable for CSAR communications, new radios will soon replace it.