DTMF Made Visible

Another bit of noodling I did over the past few days, I’m playing with the frequency mapping of the DTMF (or TouchTone™) sounds used in telephony. These tones are becoming less and less prevalent as mobile phones replace land lines, so this is something of a latter-day portrait of a mature technology. The colors are okay, but I’ll probably play with them some more. Pictured here are the ringback tone, dial tone, and busy signal. I’ll do the numberpad presently.