In a transmitter/receiver for bidirectional communication with a transmission medium, the transmitter comprises an amplifier having an input terminal for signals to be transmitted, an output stage with output terminals coupled via resistors to the transmission medium, and a negative feedback circuit connected with its input terminals to the output terminals and with its output terminal to the input terminal of the amplifier. The receiver is connected with first input terminals to the output terminals of the output stage. A current mirror is connected with its input terminal to the input terminal of the amplifier output stage and with its output terminals via resistors across a load. The load is connected across second input terminals of the receiver. The receiver is adapted to extract signals received from the transmission medium by subtracting voltages between said second input terminals from voltages between said first input terminals.