| 摘要 |
PROBLEM TO BE SOLVED: To prevent the erroneous detection of a polarity inversion that occurs before the off-hook of an opposite side telephone. SOLUTION: A voice reproducing means 10 reproduces a voice corresponding to an event that occurs, in response to a signal indicating that a polarity detecting means 8 detects a polarity inversion. When an external call apparatus 6 is hooked on, the reproduced voice can be heard by the external call apparatus 6 via a telephone line. When a communication apparatus 2 uses an internal dial tone detecting means 9 to detect a DTMF signal, and when the polarity inverting means 8 thereafter utilizes the polarity inversion to detect that a user cuts (hooks on) a telephone call from the external call apparatus 6, for example, the detection result is reported to a line disconnecting means 11. The line disconnecting means 11 hooks on the communication apparatus 2 by itself in response to the signal indicating that the external call apparatus 6 is hooked on, from the polarity detecting means. COPYRIGHT: (C)2005,JPO&NCIPI
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