Multiple use digital tone generator in telephone
First Claim
1. In an electronic telephone set having line terminals, number selection push-buttons, digital tone generator means having an oscillator having a fixed oscillator frequency and logic circuit means connected to said oscillator and comprising first frequency divider means for dividing said oscillator frequency by one of the plurality of divisors selectable under control of said number selection push buttons, a plurality of further control elements, and means for externally generating a control signal, the improvement comprising:
- detection means for detecting said externally generated control signal and generating a frequency control signal in response thereto;
additional frequency dividing means; and
means for interconnecting said additional frequency dividing means between said first frequency divider means and said selected one of said further control elements in response to said frequency control signal.
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Accused Products
Abstract
Electronic telephone set having DTMF tone dialling. By some slight additions to the logic circuits of the digital DTMF tone generator this tone generator is made suitable for generating a two-tone ringing signal, for supervising the frequency of the incoming ringing voltage and for generating a tone interval of approximately 0.1 s for the call-back function.
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Citations
7 Claims
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1. In an electronic telephone set having line terminals, number selection push-buttons, digital tone generator means having an oscillator having a fixed oscillator frequency and logic circuit means connected to said oscillator and comprising first frequency divider means for dividing said oscillator frequency by one of the plurality of divisors selectable under control of said number selection push buttons, a plurality of further control elements, and means for externally generating a control signal, the improvement comprising:
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detection means for detecting said externally generated control signal and generating a frequency control signal in response thereto; additional frequency dividing means; and means for interconnecting said additional frequency dividing means between said first frequency divider means and said selected one of said further control elements in response to said frequency control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification