| 摘要 |
PROBLEM TO BE SOLVED: To surely sense forgetting of calling a receiver of a telephone depending upon an apparatus. SOLUTION: When the telephone 2 becomes a hook-up state, a connecting sound or a busy tone is not detected, and a control means 41 detects whether it is a state in which a voice signal is not present from the receiver 3 for a predetermined time, or not based on a voice detecting means 54 for detecting only the voice signal. If there is no voice signal for the predetermined time from the receiver 3, it is judged that the receiver 3 is off the hook, the telephone 2 is disconnected from a telephone channel 9 via changeover switches 44a, 44b, and the means 41 is set to a call originating state. COPYRIGHT: (C)2004,JPO
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