FIELD: means for protection against commercial and industrial espionage. SUBSTANCE: device has series-connected auxiliary antenna and cellular-radiophone radiation detector, as well as series-connected auxiliary microphone, amplifier, amplitude detector, controlled noise generator, and masking loudspeaker. Auxiliary antenna is mounted for receiving cellular-radiophone radiation as working signal when setting radio transmission mode. Output of radiophone radiation loudspeaker is connected to starting input of noise generator. Auxiliary microphone is installed for responding to voice signals listened to by unauthorized persons; masking loudspeaker is mounted for conveying acoustic noise to cellular-radiophone microphone when dropping it in device casing and switching under effect of gravity force of power supply switch. Invention is characterized firstly in that acoustic noise generation is made impossible in absence of attempts to listen to secret talks and secondly in that noise generator is controlled to ensure that generated acoustic noise level is proportional to voice signal level. Device incorporates provision for purposeful starting and adaptation to level of masked voice signals. EFFECT: enhanced effectiveness of protection, improved comfort for conferee. 4 cl, 1 dwg
