It's the heart of an especial installation for the sound reinforcement in small town, high industrial plant for public announcement, emergency announcement etc. When the area to be conveniently covered is too large far a normal P.A. sound reinforcement installation an installation based an the  TR40401 allows transmitting audio signals up to 10km through dedicated telephone lines to amplifiers fitted with the receiving board RT40402.

• Microphone input for dynamic or condenser microphone (with PP)
• Auxiliary input (stereo-mono)
• Input/output for tape recorder
• Low and high tone controls
• Master level control
• Six output amplifiers with output transformer
• Signal generator for remote control of the receivers.