| 摘要 |
PURPOSE:To detect a fault where a hopping switch is interrupted or conducted by comparing an output signal of the hopping switch with a signal fed to the said switch to output the output signal. CONSTITUTION:If no output is fed to the, e.g., i-th transmission system from the hopping switch 2, a detection circuit 8i transmits no output signal and since a signal (e) is outputted from an AND circuit 9i with a burst signal (b) from a terminal station device 1 and a selection control signal, an output (f) of an EOR circuit 10i activates a holding circuit 12 and an alarm is raised. On the other hand, the switch 2 is conducted and all timing signals of an intermediate frequency signal (a) transmitted from the terminal station device to a terminal 2 are transmitted to the i-th transmission system, then a signal (g) is outputted from the detection circuit 8i. In this case, since the AND circuit 9i outputs the signal (e), a signal (h) is outputted from an EOR circuit 10i and the holding circuit 12 is operated. |
