| 摘要 |
PROBLEM TO BE SOLVED: To provide a function for improving hang-up recovery of DSU, especially in the case of lightning by resetting a subscriber's line autonomously in an ISDN line for a mobile communication base station equipment, etc. SOLUTION: This subscriber's line resetting equipment is installed at U point being a reference point of a subscriber and a telephone station, and it has a relay circuit 109, a hang-up detector 113 for monitoring the voltage or current of a subscriber's line for a prescribed period to detect abnormalities caused by hang-up of DSU 101, and a control circuit 110 for controlling the circuit 109. When an abnormality is detected by the detector 113, the subscriber's line is resetted (disconnected/connected or short-circuited/opened) to restore the DSU 101 to normal operation. When abnormality is detected repeatedly several number of times over a prescribed period after a relay is operated, the abnormality is judged to be a disconnection other than hanging up of the DSU 101, and resetting operation is stopped temporarily. In the case that the voltage level is resumed to be equal to or lower than about 28 V which is in normal operation, the temporary stopping of the reset operation is released automatically. |
