| 摘要 |
PURPOSE:To prevent a function of a digital exchange from being stopped by decreasing a DC current fed from each subscriber circuit to a subscriber line when the digital exchange is in the contention state. CONSTITUTION:Feeding circuits 2, 3 supply a DC current I to a subscriber line 1. A current control means 100 increases an equivalent feeding resistance in the feeding circuits 2, 3 to a prescribed value when the digital exchange is in contention and feeding control information (c) is given thereby reducing the DC current I. Thus, the DC current supplied from each subscriber circuit to the subscriber line is decreased, the load of the DC power supply is relieved and the drooping of the DC power supply voltage is prevented and the stopping of the function of the digital exchange is prevented. |
