Abstract: The structural and termination characteristics of a telephone or other wiring circuit can be determined by generating a continuous stream of low-energy electrical signals, injecting these into the circuit under test, and analyzing the energy reflected at impedance changes in the frequency domain. Standing waves occurring in the circuit can be identified as a function of frequency and analyzed to locate the impedance discontinuities. An unambiguous numerical representation of the circuit can be generated and used to categorically determine if two circuits are indeed alike, or whether the structural and termination characteristics of a particular circuit has remained the same or changed over time. Waveforms are employed that are not sensed by circuits that carry digital telephone traffic, so that the invention is useful in characterizing and providing security protection for those type of circuits in situ.

Abstract: The apparatus is a device that measures the attenuation effects of a telephone circuit's physical construction, electrical characteristics, and equipment with respect to a series of waveforms at different frequencies, then combines the resultant values to create and display a reference number called the Vasquez Number (VN), a unitless number that, once generated, becomes a representative signature of the circuit under test. This number can then be employed to compare ostensibly identical circuits, to identify aberrations indicative of wiretaps or other unauthorized equipment, or to monitor the circuit over time to determined whether such additional devices have been added.