Below are links to two PowerPoint files on Dropbox that document the technology employed in the telephone box and studio in some detail. They are stored as PowerPoints on Dropbox and are the most up to date. However they may not convenient to all users

Hardware PowerPoint (large file)
Software PowerPoint

If you would like a web version of the PPT that doesn’t require downloading please go to the links below
but they may not be the latest version.

Link to Hardware
Link to Software

In addition a full explanation of this schematic is provided in both PowerPoints.