Blackberry Dial Tone

In case anybody was wondering, the little sequence of dial tones that the Blackberry Curve 8330 makes when you hit send is the dual-tone number sequence 7933409.

I recorded the sound, analyzed it in Audacity, and found the following main frequency peaks:

  • 859 1207
  • 856 1480
  • 703 1481
  • 707 1479
  • 781 1217
  • 939 1340
  • 852 1481

These come fairly close to the following standard frequency pairs:

  • 852 1209
  • 852 1477
  • 697 1477
  • 697 1477
  • 770 1209
  • 941 1336
  • 852 1477

Which match to the keypad numbers 7933409.

Not sure what all of this means, but there's is a version of the sound generated from sequences of pure sine tones of the second set of frequencies, mixed together, and then passed through a low pass filter at a cutoff of 1600 to eliminate the clicks between silence and sound.

So 7933409 it is.