FIELD: communication. SUBSTANCE: system includes switch placed between sending and receiving subscribers, information masking device with noise generator and balance amplitude modulator and device processing masked information with digital adaptive filter and linear amplitude detector. Key and reference signals are fed into filter. First signal is mixed signal from sending subscriber and noise generator and second signal is " pure " noise. Filter handles both signals and sends information cleared of noise to receiving subscriber. Modulator is designed to supply noise level proportional to signal from amplitude detector into line of sending subscriber and into filter. The latter isolates envelope of received speech signal. Noise in line of sending subscriber appears to be proportional to envelope. EFFECT: increased efficiency of protection and adaptation to masked speech signals which secures comfort for participants of talk. 1 cl, 1 dwg
