| 摘要 |
PURPOSE:To identify a case where a fault is generated in an input signal from a case where an interface unit is drawn out erroneously, by providing a switch means to switch connection to an input side from an alarm display signal generator. CONSTITUTION:When the fault is generated in the input signal to an interface 30 current in use in a terminal equipment 1, the fact is detected by a frame detector 30-2, and the contact 30-9 of a switch is switched to (d) side. And an alarm display signal of the alarm display signal generator 30-7 is sent to an optical fiber via the contact 30-9. Since a frame bit can be detected by a frame detector 30-5' in a terminal equipment 9, no switching to a spare interface 40' is performed. Meanwhile, when the interface 30 current in use in the device 1 is drawn out erroneously, step out is detected by the detector 30-5' in the equipment 9, and a switch control signal is sent to a control circuit 50'. The circuit 50, adds the control signal on switches 20' and 20, and switches the interface from the one current in use to a spare one. |
