Abstract: The invention includes input terminals receiving electrical signals from a driver, output terminals delivering the electrical signals to a receiver, and a set of conductors connected between the input and output terminals. Also included are a coupler, its input electrically isolated from its output which includes a first segment of the plurality of conductors, a common-mode current sensor, its input including a second segment of the set of conductors, which sensor outputs a sensor signal corresponding to the common-mode current, and an amplifier having its input connected to the sensor's output, which amplifier delivers a first voltage to the coupler's input. The coupler delivers to the set of conductors a second voltage corresponding to the first voltage, which second voltage is in phase and approximately the same magnitude as the voltage creating the common-mode interference current, thereby reducing the common-mode interference current.