FIELD: telephony. SUBSTANCE: invention refers to telephones and presents modification of semiduplex loudspeaker with microphone that incorporates transmission and reception attenuators for alternate isolation of loudspeaker and microphone from telephone line. Attenuators are controlled by controller that compares signal generated by microphone with signal received from telephone line to determine which of attenuators, transmitting or receiving, should be switched on. First amplifier with controlled amplification is connected to provide for amplification of signal generated by microphone before it is fed into controller and second amplifier with controlled amplification is connected to amplify signal received from telephone line before it is fed to controller. First and second amplifiers with controlled amplification have amplification regulators so connected that amplification of first amplifier with controlled amplification decreases when amplification of second amplifier with controlled amplification rises and vice versa. Amplification regulators are manufactured with access of user of loudspeaker with microphone. Owing to this user has capability to adjust threshold at which his voice provides him with reception of telephone conversation. EFFECT: improved functional reliability of loudspeaker. 2 cl, 2 dwg
