Apple 'Monitor 100' works on GS

[spec@vax2.concordia.ca (Mitchell Spector)]

    This is rather interesting. A local person, having come across a pair
of Apple IIgs's and RGB monitors, asked for the pinouts to GS's RGB port
(seeing that he lacked a cable to connect the monitor and wanted to build
his own). I assumed he must have received an AppleColor RGB display, but
after connecting things up, he reported the screen worked fine _but_ colors 
weren't matching up. I asked for some details on the RGB monitor; he told 
me it was an Apple model 'A9M0308', beige colored case and pointed out it
had a motorized tilt screen. If I'm not mistaken, this is the Monitor 100.
A *digital* RGB display for the Apple III and IIe (with RGB adapter card).

    A few years ago, I managed to do the reverse. I plugged an analog RGB
(AppleColor RGB) from a IIgs, into an Apple III. The results were similar,
a perfectly viewable image but with color information not matching up.
How is it an analog and digital RGB screens can be interchangable? Do these
monitors have some sort of alternate mode, or the Apple III and IIgs
themselves have some way of sending out different video signals.

Mitchell Spector
spec@vax2.concordia.ca