| 摘要 |
PURPOSE:To send a same signal from each sending end by providing a means sending the same signal to plural transmission lines to a sender side, a means compensating a relative delay in the plural signals and a monitor means monitoring the transmission lines to a receiver side. CONSTITUTION:A signal received by reception sections 22, 32 are stored once in memories 24, 34. The stored signals are read synchronously with each other and fed to a changeover circuit 60. Suppose that the circuit 60 is set to select a signal sent from the sending end through a transmission line L1, and when a line fault that a signal interrupt takes place or a code error rate is deteriorated to be a prescribed value or over in the transmission line L1, a monitor circuit 23 detects it and its alarm signal is sent to a changeover control circuit 70. The circuit 70 receives the alarm signal to check the operating state of a transmission line L2 as to whether or not an alarm is raised from a monitor circuit 33. When no fault exists in the signal sent through the transmission line L2, a switching control signal is sent to the changeover circuit 60 to select the circuit 60 to the position of the transmission line L2. |
