I took part in a hackathon in Vilnius the other weekend (courtesy of Basedcollective) during the pink soup festival. I brought along an old rotary phone and our two-man team spent the next 48 hours sticking our fingers in it. We wired a Raspberry Pi into the phone which interfaced with all of its IO and communicated with our server via a single websocket connection which controlled everything from two-way audio, the bell ringer (with custom frequency and audio patterns) and the hangup switch....