| 摘要 |
PURPOSE:To transmit an AIS (alarm indication) signal through a radio digital transmission line without the influence upon the fault detection method, by transmitting only a radio section by an alarm transfer signal with the logical value changed. CONSTITUTION:When an AIS signal (a) is inputted to a transmission side A, faults of devices in preceding stages are detected by an AIS detecting circuit 7, and the AIS signal (a) and an alarm transmission signal (b) generated by an alarm transmission signal generating circuit 8 are switched by a logic switching circuit 9 under the control of the AIS detection signal, and the alarm transmission signal (b) is transmitted to a radio circuit 2. Meanwhile, in a receiving side B, the transmitted alarm transmission signal (b) is detected by an alarm transmission signal detecting circuit 10, and the transmitted alarm transmission signal and the AIS signal (a) generated by an AIS signal generating circuit 11 are switched by a switching circuit 12 under the control of the output signal from the circuit 10, and the AIS signal (a) is transmitted to a transmission line 5 of the next stage. |
