DTMF is the acronym for Dual-Tone Multi-Frequency signaling. We
all know DTMF as the tones generated by the keypad of a telephone,
also known as touch tones.
Here are some factoids on DTMF:
- According to
AT&T, commercial touch tone telephones were previewed at
the 1962 Seattle World's Fair.
- The Bell System was the sponsor of Disneyland's Circle-Vision
theater in the late 1960's. After viewing a 360° movie entitled
America the Beautiful, guests were welcomed to a hands-on
demonstration on the speed of touch tone dialing versus rotary
dialing.
- SugarLoaf's 1975 hit Don't Call Us, We'll Call You
included the sound of a touch tone phone dialing two phone numbers
- one an unlisted CBS number and the second a public number to the
White House. According to Wikipedia,
this was a practical joke on CBS Records for turning down the band
for a recording contract.
