JPH0681175B

PURPOSE:To recover a line with high reliability, by recovering the fault of the line via a timer circuit when the enquiry(ENQ) sequence of the line continues for a prescribed time. CONSTITUTION:When the fault of the line is generated and no ENQ sequency of the line is detected, the fault is informed from an ENQ sequence monitoring circuit 5 to a terminal control circuit 2, and is displayed on a CRT4. When the fault is recovered and the ENQ sequences are detected for two times consecutively, the timer circuit 6 is started up by the circuit 5, and after the detection of the ENQ sequence continuously for a set timer time, a time up signal from the circuit 6 is supplied, and the automatic recovery of the line are performed by the circuits 6 and 2, etc., and also, a normal state is displaed on the CRT4. By constituting a device in such way, it is possible to heighten the reliability of the recovery of the line.