| 摘要 |
PURPOSE:To detect easily a call acoustically and visually by connecting a telephone call display device to a telephone set main body, detecting the current flowing to a telephone set from a line and selecting a call signal from the detected signal so as to activate a moving part in response to its selection signal. CONSTITUTION:The telephone display device A is connected to a conventional telephone set T, a current detection circuit 1 of the display device A detects both a call signal and a voice signal from the line and the result is amplified (2). The signal from the detection circuit 1 is fed to a speaker 3, and a tone different from the call tone of the telephone set T is generated based on the call signal only and a prescribed moving part is activated by a means B. A signal selecting filter 5 of the means B selects a call signal, rectifies (6) the signal to activate a one-shot multivibrator 7 and its output controls an operating means 8. Then a sound output means 9 is connected to the moving part C of the case 4 of the display device A by the operating means 8 and the means 9 generates a tone different from that of the telephone set A.
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