Freeswitch is the software that connects a bunch of voice, video, sound and messaging stuff together. It is open source.
The red payphone connects to Freeswitch. The software that runs when you press keys and speak into the handset is available and open source
You can register a SIP phone to Pegasus and get a local extension on Freeswitch.
Freeswitch can record sound files. People can get these files at a URL. (tbd)
It's easy to make Freeswitch talk to you! There are some default voices built in! It's also possible to pipe text to Google Translate and get back an mp3, which can be streamed to Freeswitch in realtime. (tbd)
You can speak into the phone and your words will be transcribed. Or something. (tbd)
Freeswitch can power a realtime video conference through a web browser. (tbd)