| 摘要 |
PURPOSE:To increase automatically a call sound, when surrounding natural sound is large, by providing a sounding device which receives an incoming signal from an incoming discriminator for sounding, and where the sound volume changes in response to an output of a natural sound measuring device. CONSTITUTION:When an incoming call comes externally through a line 10, a sound indication signal 30 is outputted from the incoming call discriminator 1 to a sounding device 3. The natural sound measuring device 2 measures the natural sound under the environment where a telephone set is placed and outputs a natural sound measuring signal 20 in response to the sound volume of the natural sound. The device 3 generates sound by the signal 30 and the sound volume changes in response to the signal 20. That is, when the natural sound is large, a large incoming sound is outputted from the device 3, and when the natural sound is small, a small incoming sound is outputted. Thus, the telephone set informing the incoming call in a required, sufficient and optimum sound volume is obtained depending on the environment where the telephone set is placed. |
