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    Program to convert telephone dial tones (DTMF) to int


    While I understand that the telephone dialing uses Dual Tone Multi Frequency to generate the numbers dialed, I cannot understand how the sound can be converted to a float or int that can be interpreted by a program to give the numbers dialed on a touch telephone.
    Nor how to generate the sounds on the PC sound card when entering numbers into a numpad type form.
    Any & all suggestions would be appreciated.
    Many thanks
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  3. Sarcky
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    DTMF tones are Dual Tone and Multi Frequency. That means they are more than one sound played at once. Try to whistle a note slightly lower than the note a friend is whistling. That's a dual-tone sound, and cannot be represented by a single number nor produced by a single speaker.
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    Originally Posted by ManiacDan
    DTMF tones are Dual Tone and Multi Frequency. That means they are more than one sound played at once. Try to whistle a note slightly lower than the note a friend is whistling. That's a dual-tone sound, and cannot be represented by a single number nor produced by a single speaker.

    I appreciate your input to my question and I can understand what you are saying, but isn't an mp3 file similar, in-that you have multiple sounds being superimposed over each other.
    OR,
    Have I misunderstood and it requires multiple sounds with multiple frequencies that cannot be re-produced by a PC sound card?

    However, even if my analogy of the mp3 file is correct, I cannot see how I can compare the DTMF "sound" input into the program, with a stored file for each tone on a tone dial phone.
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    Yes, there are DTMF Mp3s but I meant it's not a single number. A computer speaker setup does indeed have the ability to produce more than one "sound" at once (32+, usually), but specifically atonal sounds are difficult. Those mp3s should be enough to get you started. Note each is labeled with the two frequencies that produce it.
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    Thumbs up


    "The light just turned on".
    After reading the link you included in your post, I think I finally have a handle on what I need to do to write the code.

    Many thanks for your assistance and patience.

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