Abstract: A line analyzer for detecting line anomalies that may be indicative of electronic tape or other surveillance related electronics coupled to a wire pair in a multiple conductor cable utilizes a switching matrix to identify possible pairings of the conductors and instruct the analyzer to selectively couple to each of the identified conductor pairings. Tests such as non-linear junction detection and frequency or time domain reflectometry operations are automatically performed on each of the wire pairs by the analyzer. The analyzer can automatically identify balanced pairs and limit the testing to the identified balanced pairs to minimize the time required for testing if desired. The results are then mathematically and graphically compared to identify wires having line anomalies. The tests can be performed over time intervals to locate transient anomalies.

Abstract: A method and apparatus for detecting concealed surveillance devices coupled to a transmission line uses either a time domain or frequency domain reflectometry operation to locate any impedance anomalies on the transmission line and a non-linear junction detection operation to classify the located impedance anomalies as semiconductor or non-semiconductor based anomalies. The reflectometry operation utilizes the reflection of a test signal to determine the distance to any reflecting impedance anomalies on the transmission line that may be indicative of an electronic device being coupled to the transmission line. The non-linear junction detection operation then compares the amplitudes of re-radiated second and third harmonics of a transmitted fundamental frequency signal to determine if the reflecting impedance anomalies are the result of a semiconductor based non-linear junction. A DC bias voltage and a balanced load may be added to the transmission line to enhance the line's response to the test signals.