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Thread: Original telephone keypad layouts - photo

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    Supporting Member Altair's Avatar
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    nova_robotics's Tools
    That's really interesting. One of those things you don't even think about. The original DTMF touch tones were created by mixing eight different frequencies, with each button representing a mix of two tones. The mixing happens in a grid that lines up with they key layouts for IV-A and VI-A (which are identical). On the early phones it would have been way easier to just run horizontal and vertical wires matching the frequency mixing. All those other layouts would have complicated the phone design. Bet the bean counters made the final decision on which keypad layout was the winner.

    https://en.wikipedia.org/wiki/Dual-t...gnaling#Keypad


    There used to be a a thing called "phone phreaking." It was started by a guy named John Draper who found that blowing a small toy whistle from a Captain Crunch cereal box into a phone receiver would get free calls on payphones. It's a pretty interesting rabbit hole that involves a lot of figures like Steve Wozniak.


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    Floradawg (Feb 27, 2024)

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    nova_robotics's Tools
    Another video. The history of it all is pretty interesting.


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    ductape (Feb 27, 2024), Floradawg (Feb 27, 2024)

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    Supporting Member Floradawg's Avatar
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    Floradawg's Tools
    Even if you only drink "regular" coffee you are consuming a higher quality of coffee than from decades ago. Most of it then was Robusta. Most of what is available today is Arabica, usually considered to be superior to Robusta. So if you're old like I am and you hated coffee when you were a kid, you may like it better now. Or maybe not.



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