DTMF (Dual-Tone Multi-Frequency) dialer, Bluebox, and Redbox.

Now in a release-ready state for both Dialer, Bluebox, and Redbox (US/UK) functionality!

Please note that using the current tone output method, the 2600 tone is scaled about 33 Hz higher than it should be. This is a limitation of the current sample rate.

• http://www.phrack.org/issues/25/7.html#article
• https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling
• https://en.wikipedia.org/wiki/Blue_box
• https://en.wikipedia.org/wiki/Red_box_(phreaking)