Hierarchy
Description The sound of a telephony signaling system where short combinations of tones within the frequency range of human speech are used to transmit individual digits.
URI http://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling
Siblings
Examples
# audio samples
212
# ground truth
76     (propagated from children: 0)

Audio samples with candidate annotations for
Telephone dialing, DTMF