I was expecting it to be a pet project that took an old telephone that had the extra ABCD keys, run it through an arduino/AVR and into a USB port. https://en.w

I was expecting it to be a pet project that took an old telephone that had the extra ABCD keys, run it through an arduino/AVR and into a USB port. https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling#/media/File:DTMF_keypad_layout.svg https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_sign... https://www.tech-faq.com/abcd-tones.html https://www.tech-faq.com/abcd-tones.html