This project (Project ARC) is a spin-off from my Sphere-1 reconstruction project, in that it provides additional functionality (in the form of an RS-232 interface) which was not present on the original CPU/2 board.
Additional components would need to be purchased.
This project aims to make adding RS-232 capability to the CPU/2 board simpler and more modular in its approach.
The documentation is stored on Google Docs for reference - the link is below.