| 摘要 |
PURPOSE:To monitor a fault of a transmission circuit and a reception circuit at all times by applying speed conversion to a reception signal when the reception signal passes through the reception circuit, multiplexing a transmission signal as fault monitor information to apply fault monitor. CONSTITUTION:A transmission signal inputted from an input terminal 1 and a reception signal from an input terminal 4 through a line interface 5 are multiplexed in the unit of one time slot by a multiplex circuit 8. On the other hand, a transmission signal demultiplexed by a demultiplex circuit 9 is compared with the transmission signal from the input terminal 1 delayed by a delay time equivalent to a passing time of a transmission circuit 6, the multiplex circuit 8, the reception circuit 7 and the demultiplex circuit 9 at a delay circuit 12 by a check circuit 14, in which a fault in the transmission circuit 6 and the reception circuit 7 is detected and the result of fault detection is outputted from a detection result output terminal 15. Thus, even in the transmission/ reception of the transmission signal and the reception signal, a fault is detected by the transmission circuit and the reception circuit. |
