Abstract: A system which monitors telephone lines includes the capability to detect abnormal line conditions of many varieties. Such detection capabilities include physical damage such as cut line, misuse such as leaving a handset off-hook for an extended period of time, and intentional abuse such as a wire tap. The system is flexible enough to automatically adjust to varying `normal` conditions. As an aid in providing reliable telephone communications, the system will generate immediate alarms upon detection of abnormal conditions and concurrently create a historical database. This database is used to review reliability and response times, identify hardware failure trends or repeated misuse, and provide system management reports so as to adjust to varying normal conditions without generating false alarms. The physical system contains circuitry to scan the incoming telephone lines.