| 摘要 |
PROBLEM TO BE SOLVED: To provide a portable telephone set in which an incoming call tone speaker requiring a large volume and a calling speaker not requiring a large volume can be used in common in a single speaker. SOLUTION: The telephone set is provided with an incoming call tone output circuit 531 for outputting an audio signal, an incoming call tone volume limiting circuit (532, 533 and 534) for limiting the volume of the incoming call tone represented by an output signal of the circuit 531, and a single speaker 57 for emitting sound according to an audio signal of a speaking voice or an output signals of the circuits (532, 533 and 534). When the volume of the incoming call tone represented by the output signal of the circuit 531 exceeds a reference volume continuously, the circuits (532, 533 and 534) limit the increase speed of the volume exceeding the reference volume.
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