Happy 50th DTMF

1   1   2   1   6   3-   1   1   2   1   9   6

1   1   #   9   6   3   2-   #   #   9   6   9   6

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The DTMF generator above has the ABCD key sequence from the Silver Box – phone phreak phavorite.

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1209 Hz 1336 Hz 1477 Hz
697 Hz 1 2 3
770 Hz 4 5 6
852 Hz 7 8 9
941 Hz * 0 #

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DTMF signalling is celebrating its 50th anniversary this week – let’s celebrate with a little music.

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Touch Tone via Archive.org

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