Abstract: The present invention relates to a method for distinguishing between an open conductor and a proper termination of a telephone subscriber loop which is terminated with a telephone which does not conform to the ringer-equivalence standard of the FCC Rules. In this invention a telephone subscriber loop can be tested for an open or for a termination by a customer provided equipment telephone by obtaining a first ratio of the tip-to-ground impedance relative to the tip-to-ring impedance; and a second ratio of the ring-to-ground impedance relative to the tip-to-ring impedance, and comparing each of these ratios relative to a fixed ratio value. If the measured ratios are substantially equal to or greater than the fixed ratio value, the subscriber loop is terminated with a customer provided equipment telephone. The fixed value may be dependent upon the length of the loop and whether or not a maintenance termination unit is present in the loop.