| 摘要 |
<p>PURPOSE:To allow a master station side to discriminate whether a faulty location exists in a master station, a slave station or a transmission section by using the combination of loopback test and an alarm indicating a fault of a slave station reception section. CONSTITUTION:A master station test circuit 11-3 uses a timer to generate an output (a) periodically, which is inputted to a master station transmission section 11-1. The transmission section 11-1 uses it to generate a signal (b), which is fed to slave stations as a test signal 13. The signal 13 is received by a slave station reception section 12-2, retransmitted via a slave station test circuit 12-3 and becomes a signal (c). The signal (c) is fed to a slave station transmission section 12-1 to generate a signal (d), which is transmitted to a master station as a test signal 14. The signal 14 is received by the master station reception section 11-2 to generate a signal (e) and returns to the master station test circuit 11-3. The loopback test is executed in this way and when the signal (e) is not returned to the master station test circuit 11-3 via the slave stations regardless of the generation of the test signal (a), it means that either the transmission/ reception section of the master station or a slave station is faulty, an alarm ALMB is raised from the master station test circuit 11-3.</p> |
