OpenPayphone

First public release of OpenPayphone — open-source software and hardware that revive a 1996 Ernest D3 COCOT payphone, replacing its internals with a Raspberry Pi Zero, an IQaudIO Codec Zero (DA7213), an AG1171 SLIC, and a custom HAT to make a working SIP/VoIP payphone with authentic coin handling.

Highlights

• SIP calling via pjsua2: dial-plan routing, DTMF, and call-progress tones
• All-or-nothing coin escrow with overtime deposits and a hold-# refund backdoor
• Hardware tone generation on the DA7213 codec (calibrated, zero CPU)
• Event-driven multiprocess core with a typed event bus and a phone state machine
• Board hardware-abstraction layer with a mock backend and a pytest CI suite
• Flask web admin UI: config, rate plan, cash/call tracking, system + logs
• Independent call/cash recorder with retention
• Standalone install.sh, packaging, and CI; KiCad PCB, BOM, and enclosure parts

See CHANGELOG.md for the full feature history.

Install: download the tarball, unpack on a Raspberry Pi, and run sudo ./install.sh (see README).