The FDR measurement mode provides a means of characterizing impedance mismatches in the home wiring and is used to detect potential faults that could disrupt signal transmission.

A frequency domain reflectometry (FDR) test reveals the location and severity of sources of reflections. This facilitates the replacement of faulty cable and components or the repair of craftsmanship problems. FDR is used with the JDSU LST-1700 Signal Transmitter which provides a source for a frequency domain reflectometry test of home wiring to help locate faults.