| 摘要 |
<p>PURPOSE:To find out a fault of a switch early by providing a fault check code addition circuit adding a fault check code to a data to an input stage of the switch and providing the fault check circuit to an output stage of the switch. CONSTITUTION:Fault check code addition circuits 13a, 13b are inserted respectively in lines L10a, 10b through which a data going to a switch 12 is sent from subscriber circuits 11a, 11b to test the switch 12. Moreover, fault check circuits 14a, 14b are inserted respectively in lines L11a, 11b through which a data going to a switch 12 is sent from the subscriber circuits 11a, 11b. The fault check circuit 14b detects the presence of a fault based on an added FCS code FCS, annunciates the fault when the fault takes place and eliminates the FCS code FCS when no fault exists, the data is restored to the original data DAT 1 and the result is outputted to a terminal equipment 10b.</p> |
