It was a long overdue "work in progress" but I finished updating my old eBay guide to make a Help/AC3RF section on LDDb:
http://www.lddb.com/help_ac3rf.phpI still need to make fresh APD-1 and RFD-1 pictures but could you double-check my writing for typos/errors?
Next update would be to add a "Soundtracks" help section to explain the difference between analog, analog-CX, digital, multi-audio, AC3, DTS, etc.
Julien