| 摘要 |
PURPOSE:To avoid the fault of the whole of a system by preventing an abnormality from having an influence upon the other all network systems and disconnecting only a faulty part if the abnormality occurs in a part constituting the network system. CONSTITUTION:If an illegal modulated waveform is continuously received and normal transmission cannot be performed for a long time because of the occurrence of trouble in a bus type transmission line 22, a signal monitor circuit 4 of remote repeaters 26 and 27 connected to the bus type transmission line 22 detects the signal abnormality of the bus type transmission line 22. Then, the signal monitor circuit 4 de-energized a permission signal 12, and conditions are not satisfied in either of a transmission gate 5 and a reception gate 8, and the output is not energized. Consequently, the bus type transmission line 22 is disconnected from the other network systems. Thus, the system is degenerated to the network system having only a bus type transmission line 21 and network systems having bus type transmission lines 23 and 24 and continues the operation. |
