| 摘要 |
PURPOSE:To make it possible to perform remote diagnosis even for simultaneous faults of the trunk circuit and make it possible to disconnect faulty parts and shorten the time for recovery, by executing the remote loop test as well as the remote inquiry program from the network centralized control unit. CONSTITUTION:Network centralized control unit NCC transmits inquiry message HCK3 through control line CL3. When receiving it, repeating exchange NP3 transmits inquiry messages HCK3S, HCK2, and HCK5 to the data terminal and repeating exchanges NP2 and NP5 through subscriber's line SL and trunk lines TL23 and TL53 respectively. When receiving response messages RSP3S, RSP2, and RSP5 corresponding to them, NP3 decides whether these response messages are correct or not, and the result is returned to NCC as response message RSP3 through control line CL3. Thus, the fault of NP3 and the fault of each line related to it can be discriminated from each other easily. Next, the remote loop test is executed for the line system which is decided as faulty, and the test is executed which discriminates the fault in the exchange and the line fault from each other. |
