| 摘要 |
PROBLEM TO BE SOLVED: To allow a digital service unit DSU with a multi-channel making communication between an ISDN exchange and a user terminal to quicken a fault location by discriminating propriety of a synchronizing system circuit on the occurrence of a communication data error. SOLUTION: Two communication channel modules (hereinafter called modules) that are diagnostic objects are selected (S1). First and second communication states corresponding to the respective modules are received (S2, S3) and whether or not each module is in a communication state is discriminated, and whether or not both the modules are in the communication state is confirmed (S4, S5). When the both are in the communication state, each synchronizing timing or the 1st communication and the 2nd communication is extracted (S6, S7), and whether or not phases of both the extracted synchronizing timings are coincident is discriminated (S8). When the phases of both the extracted synchronizing timings match with each other, it is recognized that the synchronization system circuits of both the modules are normal (S9), and when unmatched, it is recognized that the synchronization system circuit of either of the modules is faulty, and similar processing to the above is conducted by combining the module causing the dissidence with other normal module (S10). |
