Patent ID: 8300771

Claim:
A method for determining whether a state of loop termination of a loop is short terminated, open terminated, or terminated by a matched-impedance, the method comprising: receiving an un-calibrated echo signal for a loop under test using frequency domain reflectometry single-ended line testing (FDR-SELT), a loop length estimate of the loop, a region, and a platform specification; determining coefficients corresponding to each of a predetermined set of tones, wherein the set of tones is a function of loop length, and wherein the coefficients are determined based on the specified region and platform; determining phase thresholds for the predetermined set of tones based on the determined coefficients and loop length such that the phase thresholds at the predetermined tones correspond to polynomial-fitted decision phase values that are a function of loop length for the received region and platform; and comparing the phase thresholds with corresponding phases of a filtered echo signal at each of the set of predetermined tones and determining whether the loop is terminated by an open or short termination at each of the predetermined tones.