PURPOSE: To restore the state of permanent loop from out of subscribers, by providing a means monitoring the time of permanent loop for a subscriber circuit, and informing the generation of the permanent loop to the other parties.

CONSTITUTION: In a subscriber circuit LC, terminals 1, 2 are connected to a telephone set EXTA and terminals 3, 4 and 5 are connected to a main link. Terminals 6 and 7 are connected to a busy tone and howler oscillator, and terminals 8, 9 are connected to a pickup pulse circuit (not shown). A terminal 10 is used for the information of a permanent loop for a prescribed time or over to a common controller CC. In this circuit, a relay H starts slow restoration with the operation of a pickup relay B, and when a relay H is completely restored, the information that the permanent loop continues for a prescribed time or over is informed to the common controller CC through the terminal 10. Thus, the common controller CC processes to inform a predetermined device.