The Previous poster has inaccurate information.
There is a PLATO installation that has been set up for retrocomputing users @ IRATA.ONLINE. If you go to the website, you'll find information about the service, how to connect, as well as a technical section that is full of information on creating terminals to use with the service. Thus far, we have a working terminal implementation for Atari 8-bit machines, with more on the way. We also provide two source code implementations in C, and a link to a disassembly of the Atari PLATO cartridge on GitHub.
Currently, retro-computers can log onto both Cyber1.org and IRATA.ONLINE via an emulated internet modem, built from devices such as:
- A Lantronix MDS terminal server, or
- A Raspberry Pi running tcpser and an appropriate USB to RS232 cable, or
- A specialized device running on e.g. an ESP8266 or ESP32 microcontroller providing the TCP bridge to either RS232 or other native bus. One is being developed for the Atari 8-bit computers, now.
IRATA.ONLINE also hosts multiple meets on the weekends, to demonstrate the system, and talk with potential users, authors, and systems programmers (the latter hopefully to help write terminals).
With the combination of a rich and capable delivery protocol, a built in programming environment, and the pervasive inclusion of social networking features, retro-computing users will finally have a killer app that they can connect to, because an Atari 8-bit can't log onto Facebook, a Commodore 64 can't log onto twitter, nor can an Apple II go onto Instagram.
IRATA.ONLINE is being run as a pure labor of love, with zero commercial connection to it, there is no data gathering, no access or subscription fees, just a place to connect for retro-computers of all shapes and sizes.