TEILNEHMERLEITUNGSTESTSYSTEM

A slave unit (10) for being used in a system (12) for testing a telecommunication line (14) is provided. The system (12) includes a central unit (16), at least one said slave unit (10) and threshold detection means (36). The central unit (16) includes signal generation means (20) capable of generating a test signal (26) of increasing amplitude or frequency and is operatively connected to an exchange end of the line. The central unit further includes comparator means connected to the signal generation means. The slave unit (10) is connected in use to a subscriber unit end of the telecommunication line (14) and is operable under control of the central unit (16) selectively to disconnect the subscriber unit. The threshold detection means (38) detects when the test signal (26) reaches a predetermined threshold and, in response thereto, the comparator means (38) compares the predetermined threshold with the amplitude of the test signal (26) applied to the telecommunication line (14) when the predetermined threshold is reached. From the comparison line attenuation may be determined.