| 摘要 |
<p>The transmission line control system according to the invention is capable of disconnecting and reconnecting a terminal communication apparatus (S1, S2..Si) from and to a main transmission line (L) reliably and quickly on such occurrences as a fault on the line, correction of the fault, and cutting off and turning on of a power source. The control system includes, for each terminal communication apparatus, two subsidiary communication lines (M1,M2), a by-pass (BPi), two signal monitoring devices (W1,W2), and four change-over switches (C1-C4). Each signal monitoring device monitors a data signal passing through the subsidiary transmission lines and controls the switching operation of the change-over switches so that, upon occurrence of a line fault or a disconnection of the power source, only the terminal communication apparatus related to the trouble is disconnected from the main transmission line and that, upon correction of the line fault or turning on of the power source, that terminal communication apparatus is reconnected to the main transmission line. In order to perform such control operation properly, constants deciding the lengths of time of operation of the signal monitoring devices are determined to satisfy given inequalities. </p> |
