| 摘要 |
PURPOSE:To make even a person at a remote location or a person nearby to listen to a pleasant ringer tone by decreasing the tone volume of a ringer of a telephone set at first with a low tone color and increasing the tone volume as time elapses while increasing the tone color. CONSTITUTION:A tone volume variable circuit 13 and a tone color variable circuit 14 setting a ringer tone of a ringer circuit 11 are provided and an electronic control circuit 15 controlling the tone volume variable circuit 13 and the tone color variable circuit 14 as a call time elapses is provided. When a call signal is fed to subscriber lines L1, L2, the electronic control circuit 15 is started. As the call time elapses, the electronic control circuit 15 changes the resistance of the internal circuit of the tone volume variable circuit 13 and the tone color variable circuit 14. Thus, the ring setting condition of the ringer ringing circuit 11 is changed to increase the tone volume of the ringer gradually and to change the tone color higher thereby allowing a person nearby and at a remote location to listen to pleasant ringer tone.
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