PURPOSE: To shorten the time required for cutting off a fault, by providing a 1st controller for folding of private line of an unattended station and a 2nd controller for folding of private line of another unattended station provided with a function for accessing a housed private line.

CONSTITUTION: The PCM signal line monitoring device provided at an unattended PCM terminal station is used as a control monitoring system. Namely, a folding controlling section which controls the folding of the transmission line of a circuit to be tested or the folding of a terminal LB through remote control from an attended station, operation monitoring section which monitors the operating procedure and operation of a device and prevents malfunctions, and a 1st folding controller LB CONT-A with a built-in I/O interface section which performs transmission-reception of signals with the PCM signal line monitoring device, are provided. In addition, a 2nd folding controller LB CONT-B with a built-in circuit accessing section which performs transmission line folding or terminal LB folding on a circuit to be tested in accordance with the information from the 1st folding controlling section LB CONT-A is also provided. Therefore, cutting off of initial operation can be performed quickly and adequately and a faulty time can be made shorter.