A raw 8000 Hz audio stream of the DTMF sound produced by the "7" key on a touchtone phone (this is a "pure" digital sound). Contains a series of 2048 signed 16-bit little-Endian samples. Has strong frequency peaks at 852 Hz and 1209 Hz. Useful input data for any program manipulating an audio signal; originally created for [[Cooley-Tukey FFT algorithm (C)]].