| 摘要 |
PURPOSE:To make exchange connections by using a circuit connected to a different frame when a digital circuit extending to a master circuit runs into trouble, by providing a circuit change-over circuit that connects the digital circuit, extending to the master station, to the digital circuit from the other frame. CONSTITUTION:When the digital circuit connected to line frame 100 is in trouble, control circuit 100-16 recieves and monitors control information from control circuits 200-16 and 300-16 of line frames 200 and 300. On receiving the information, control circuit 200-16 sends the information to control circuit 100-16 and also controls change-over circuit 200-17 to connect CODEC 100-10 to master-station/digital-circuit interface circuit 200-13. Further, control circuit 100-16 controls change-over circuit 100-20 to connect interface circuit 200-13 to CODEC 100-10. Namely, calls of subscribers equipped in line frame 100 can be connected to the master station via interface circuit 200-13 of line frame 200 and the interruption of exchange services for subscribers equipped in line frame 100 can be evaded. |
