| 摘要 |
PURPOSE:To allow a person at a location remote from a telephone set to be able to listen to a telephone ringing tone by increasing the volume of telephone ringing tone as the number of times of ringing increases. CONSTITUTION:The titled circuit consists of a bell signal detection circuit 1 detecting a bell ringing (a) received from a line, a counter 4 counting the number of times of a bell driving signal (b) outputted from the circuit 1 and outputting a level adjusting signal (c) to adjust the driving level when the number of times reaches the predetermined number of times, a bell driving circuit 2 receiving the bell driving signal (b) and the level adjusting signal (c) to drive the bell 3 and the bell 3 driven by the circuit 2. It is possible to increase the bell driving tone level gradually as the number of times of bell ringing by supplying plural counts in advance to the counter 4. If the called party resides in a remote location and cannot listen to the ringing of bell, since the tone level is gradually increased as the time elapses, the called party can be noticed thereof.
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