CHECK DEVICE FOR TRANSMISSION SYSTEM

摘要

PURPOSE:To eliminate troublesome connection and to cope with a fault quickly by connecting the titled device with a node unit in a form of an electric signal and sending/receiving a data signal and a control signal. CONSTITUTION:In the normal operating state of the node unit 10, a 2-way optical loop signal is intercepted during the sending system operation state via terminals 105, 106 by connecting a check device 11 to the node unit 10 with a connection cable 140. In inserting a pseudo data signal of the check device 11 to the 2-way optical loop, a control signal from a central processing unit 171 is transferred to an interface circuit 129 through a terminal 109 from a terminal 149. A central processing unit 131 keeps the level of terminal B of the data selectors 124, 125 to an H level. Then the terminal A of the selectors 124, 125 to the L level is controlled to attain the transmission m mode from the check device 11 and the device 11 is replaced with the node unit 10 to send the pseudo data signal for check to the 2-way optical loop as an optional binary signal from a switch of an operation section 174.