in general , in one aspect , the disclosure describes a digital network to telephone interface device having a controller capable of detecting foreign voltage faults without interrupting telephone service . upon detection of a foreign voltage fault the controller can deactivate the telephone service and initiate a test sequence to confirm the foreign voltage fault . if the fault is confirmed the telephone service remains deactivated and an operator of the digital network is notified . the device will improve the quality of service and save the cost of sending some one to investigate the fault . the operator can take proactive action once the device provides fault analysis and information remotely .