PERMANENT HOOK-OFF PREVENTION METHOD

摘要

The method for automatically cutting off a hook switch when a handset is misplaced in a telephone system comprising the steps of: initializing a past value of a level count and a threshold value of a specific signal level, initializing an idle state value for a prescribed time, counting an energy variation value and a frame value for a prescribed time, and storing the number of frames exceeding the threshold value as the frame value; judging an alternative current hum, a silence state, etc. according to the frame value; and if the idle state value is under a given value, restoring the state of a hook switch, thereby providing efficient service.