| 摘要 |
<p>PURPOSE:To detect a line discontinuity state or the like due to an open line or a fault of a station by detecting a line-voltage state of a public communication line and a current state flowing thereto so as to discriminate whether or not the line is normal. CONSTITUTION:When the line is normal, the line voltage is a prescribed level or over or the level of a current flowing to the line is a prescribed level or over. Then the state of the line voltage and the stage of the current flowing to the line are detected by the 1st and 2nd detection means 10, 20 and the result of detection is given to a discrimination means 30. The discrimination means 30 discriminates whether a fault takes place in the line based on the result of detection or not and raises an alarm tone when a fault takes place in the line 2 based on the result of discrimination. Thus, the discontinuity state or the like due to an open communication line or a fault of a station is detected.</p> |
