| 摘要 |
PURPOSE:To secure an early detection of the fault caused by the quick partition of the loop deciding through the decision circuit whether the signal of the normal code system or the code of the loop-back code system and then forming the loop- back circuit of an optional repeating section based on the result of the above decision. CONSTITUTION:When the loop-back is carried out between the transmission devices which are distant away from each other, bipolar signal transmission circuit 12-4 converts the data code system of the normal transmission time into the code system for loop-back for transmission. With reception 12-6 of the transmitted signals, decision circuit 12-5 decides whether the signal is the signal of the normal code system or the signal of the loop-back code system. Thus, the loop-back circuit is formed by the result of the decision for an optional repeating section. As a result, an early detection is possible for the falut caused by the accelerated partitioning of the loop. |
