Yes, the classic Model 2500[1] touch tone phones would do this. It allowed you to play a more musically pleasing version of "Mary Had a Little Lamb", without th

Yes, the classic Model 2500[1] touch tone phones would do this. It allowed you to play a more musically pleasing version of "Mary Had a Little Lamb", without the dissonance you got when pressing single keys. This was a side-effect of how the old, mechanical keypads were built. You can see what the keypad looked like in the first minute of this video: https://www.youtube.com/watch?v=JfEUxHIDzPE https://www.youtube.com/watch?v=JfEUxHIDzPE [1] https://en.wikipedia.org/wiki/Model_500_telephone#Model_2500 https://en.wikipedia.org/wiki/Model_500_telephone#Model_2500