Help w/ NEC Multisync 3d and TTL

[Steven Hirsch <snhirsch@gmail.com>]

I'm not sure where else to turn for help with this.  I'm trying to use my NEC 
Multisync 3d with a variety of older computers that operate at 15.7khz Horz 
scan frequency - Apple IIgs, Atari ST, Commodore C128, etc.

Unfortunately, I do not have the adapter that NEC offered to convert the 
captive HD15M on the monitor to 9-pin connectors.  I've scratched my head over 
the user manual and a fuzzy copy of the service information and still can't 
make heads or tails out of it.

The service manual lists the following signals as being valid when in TTL 
(EGA/CGA) mode:

RA GND
r
R
g
V.D
H.D
G
B
b

So, what is that trying to convey?  The V and H sync are somewhat obvious, as 
are R,G,B.  So, what are the lowercase r,g,b? Inverted polarity?  Different 
levels?

Is "RA GND" just simply ground or is it something else?

Does anyone reading this group have the original adapter?  Are you willing to 
ring out the connections?

If it will help, I can forward PDFs of the pertinent portions of the schematic 
on request.

Steve