METHOD AND EQUIPMENT FOR SWITCHING MULTIPLEX TRANSMISSION LINE

PURPOSE:To improve the maintenance maintenance property and reliability by sending simultaneously a data to all multiplex system transmission lines to apply self-diagnosis in case of transmission, disconnecting a transmission line if it is decided that the inside of its own station has an error and receiving the data only from a transmission line decided as normal in case of the reception. CONSTITUTION:A data sent to transmission lines 10, 11 is subjected to normality/ abnormity decision by a deciding circuit 52. Then the result of decision is sent to a transmission line diagnostic circuit 58 to repeat the diagnosis of the transmission line. When the fault is detected, the relay of the corresponding transmission line side is opened to apply self-diagnosis in its own station. As a result, when it is normal, the relay is reconnected and when an error still exists, the relay remains disconnected as it is. The data on the transmission line 10 is received via a reception circuit 52, the normality/abnormity decision of the reception data is applied in the deciding circuit 52, and only when the data is normal as the result of decision, a timer 53 is reset. When normal reception is not executed, the timer 53 is not reset and the changeover command of the reception line is given to a reception line indicator 57.