| 摘要 |
<p>PURPOSE:To obtain a line interruption alarm signal without giving any effect on line, by providing a conductor for detection other than the line along the line and monitoring this conductor to obtain a line interruption alarm signal. CONSTITUTION:A telephone line conductor 9 connecting an exchange station 7 and a terminal device 8 such as telephone set is insulated electrically from a detecting conductor 5. Further, an interruption monitor circuit 6 has the conductor 5 and connecting terminals AL1, AL2, and a current detecting circuit 22 consisting of a relay RL operated with the switching of the terminal AL1, AL2. The interruption alarm signal is obtained with a relay contact rl of the relay RL.</p> |
