Telephone lines can have discontinuities caused by line faults, coils and bridge taps that impede transmission. Telephone companies (telcos) must locate and repair these faults in order to enable high-speed data transmission. It is useful for a telco to 'prequalify' lines for future DSL services, so a customer can be promptly informed if high-speed services can be supplied This paper proposes a new technique called frequency domain reflectometry (FDR) to accurately locate impairments in telephone lines and determine the reflection magnitude caused by faults. The measurement produces a result similar to the well-known time domain reflectometer (TDR); however, DSP techniques are now applied to provide enhanced resolution and range beyond 3 km. In addition to reflection magnitude, the new technique can measure reflection angle which helps determine the nature of the fault (open circuit, short circuit, broken wire, coil, etc.).