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Comment by mediaserf | Hacker News Reader
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mediaserf
·
440 Hz is also the standard telephone dial tone in the US.
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sp332
·
Dial tones are a chord of 440 and 350
https://en.wikipedia.org/wiki/Precise_Tone_Plan
This follows on from DTMF's use of pairs of tones for signalling.
https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_sign...
finnh
·
I love the scene in Adaptation where a tripping Meryl Streep and Chris Cooper harmonize the dial tone chord while talking on the phone.
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