Abstract: A line driver for connection to a transmission line having a characteristic impedance. The line driver can be arranged in a voltage-mode or a current-mode configuration. In the voltage-mode configuration, the line driver comprises an amplifier, a transformer, a reference resistor and a feedback circuit. The first winding of the transformer has a first end connected to the output of the amplifier and the second winding is connectable to the transmission line. The reference resistor has an end connected to the second end of the first winding at a junction point and the feedback circuit is connected to the input and output of the amplifier and also to the junction point. The reference resistor has a resistance equal to {fraction (1/k)} times the characteristic impedance of the transmission line. The feedback circuit is arranged to produce a voltage at the output of the amplifier substantially equal to −(K−1) times the voltage at the junction point, for a predetermined value of K.