A method and related system calibrating downhole tools for drift. The SQL statement includes a particular operator that operates on a first instance of XML type that represents a first set of XML elements. The contact configuration has a high degree of redundancy in providing electrical communication between the socket and plug, and high contact stability under mechanical load. The method also includes comparing the correlation results to a threshold value to generate a minimum chromatic dispersion value and a maximum chromatic dispersion value, and performing filter processing for the output of the OTDR based on the minimum chromatic dispersion value and the maximum chromatic dispersion value. The photoconductive switch and the photodetector are arranged such that the switch light signal does not interfere with the optical signal at locations proximate to the electrode and the electrode has a length that is less 0.