LINE CHECKING SYSTEM FOR TELEPHONE

摘要

The subscriber's system detects the short or the cut-off state of subscriber's line and generates an alarm signal without the help of a station. The system includes a rectifier for rectifying a signal transmitted from a station, a cut-off state detector for discriminating cut-off state by inspecting the rectified voltage level, and an alarm signal generator for generating alarm signals according to output signal of the cut-off state detector.