Abstract: Methods and apparatus are disclosed for identifying defective communications lines. The method generally involves passively detecting signals symptomatic of and generated by a defective communications line rather than by a user accessing a communication network via the line. One alternative involves monitoring calls to a selected number having low digit and set values. Analysis of the pattern of calls to the selected number, or directly monitoring the frequencies upon the communications line, identify calls that are effectively generated by defects in a communications line rather than legitimate calls generated by network users. Spurious calls are associated with the originating communications line. The line can then be automatically tested or service dispatched. More automated alternatives are also disclosed that make use of switch reconfigurations. Central office switches may be programmed to detect a variety of events that indicate a spurious pulse or seizure is being generated by a communication line.