The invention relates to an information signal processor, etc. The network address mapping system can identify a set of Web pages, collects information from the Web pages indicating geographical locations, and correlate the geolocations with the network addresses from which the identified Web pages are served. The method comprises estimating a pilot noise variance based on a pilot signal received from a base station on a downlink and estimating a data noise variance based on a data signal received from the base station on the downlink. A determination is made that a plug is present in the plug aperture based at least in part on detecting the electromagnetically coupled control signal on the first differential pair of conductive paths.