OpenPayphone – open-source guts for a 1996 coin payphone (Pi and SIP)

OpenPayphone replaces the internal electronics of a classic 1996 coin payphone with a Raspberry Pi and open-source software, enabling it to function as a modern VoIP phone using SIP. It is designed for hobbyists, retro-tech enthusiasts, and makers who want to restore or repurpose vintage payphones for practical use. The project is interesting because it blends nostalgic hardware with contemporary open-source technology, preserving a piece of communication history while making it fully functional on today's networks.