Communication interface and testing method therefore

A method for testing a bidirectional communication interface comprising a transmitter and a receiver connected to a same transmission line, wherein

• a) a test signal in a first frequency range is repeatedly emitted by the transmitter, each of said emitted test signals being associated to a reference time mark,
• b) response signals in a second frequency range associated to said test signals are received at the receiver such that the reference time marks of their associated test signals are synchronized, yielding a superimposed response signal,
• c) based on the superimposed response signal, the interface is judged to be in order or not in order.
• And wherein
• in a first phase of step a) the transmitter is amplitude controlled to emit the test signal in a first frequency range at a first amplitude, and in a first phase of step b) a first amplitude of the response signal received at the same time at the receiver is detected,
• in a second phase of step a) the transmitter is amplitude controlled to emit the test signal at a second amplitude, and in a second phase of step b) a second amplitude of the response signal received at the same time at the receiver is detected,
• and in step c) the interface is judged to be in order or not in order based on the first and second amplitudes of the superimposed response signals obtained in said first and second phases, respectively.