Re: RGB monitor on a IIc+

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

In article buggie@pegasus.unm.edu (stephen e buggie) writes...

>Will teh RGB converter for IIC PLUS also work with IIC?

    Absolutely, the Video Expansion Port on the Apple IIc Plus
is identical to the one on the original Apple IIc. There is no
difference between them.

>CGA --- that means IBM style color monitors?   With the adaptor, which
>version gives the sharpest picture:  CGA or RGB (IIgs monitor type)?

    CGA monitors used digital RGB (which has a limit of displaying
64 colors) whereas the AppleColor RGB used analog RGB (which can
display an unlimited amount of colors). That is irrelevant on a
machine such as the Apple IIc, which can display only a maximum
of 16 fixed colors.

    As to which one is sharper, that would depend on the quality
of picture tube and dot-pitch. In general, the AppleColor RGB is
much sharper and clearer than most of the old CGA/EGA monitors
I've seen over the years. I may be mistaken, but I don't believe
analog RGB has any image advantage over digital RGB (color aside).

>Also, what are the prices of the CGA version vs. RGB version??

    You seem to be confusing the terms "CGA" and "RGB". The term
CGA stands for Color Graphics Adapter, a video standard used by
the IBM in the early 80's. Monitors that worked with this type of
video (NTSC frequency, digital RGB) were called TTL, CGA or EGA
display monitors (EGA is another digital RGB video standard--
short for Enhanced Graphics Adapter).

    RGB stands for Red-Green-Blue, which is what how an RGB monitor
works. The color information in the video signal is split into three
independant lines (a red line, blue line and green line; digital RGB
monitors carry a forth line for brightness to display 16 colors, or
6 lines to display 64 colors because lines are either on/off whereas
analog varies the voltage to each line, so it only needs 3 lines).

    All you really need to know are digital RGB monitors will work
with the IIc if you have an adapter. As for analog RGB monitors,
you need an adapter which supports them and I'm not sure if that
actually exist (if not, you'll get a picture but the colors will
be wrong and in some cases, missing). Modern day monitors are also
analog RGB, but they use higher frequencies which make them not at
all compatible (avoid SVGA and Mac monitors).

>Is there an RGB adaptor that will run a CGA monitor on a IIe?  I use a IIe
>at the college; my college can provide an IBM-style color monitor if I ask
>for it.

    Yep, the ColorLink piggyback option for the AE RamWorks card
is one example, another is the Apple Extended 80/RGB card. Both
plug into the auxiliary slot and allow you to drive a digital
RGB monitor (IBM CGA and EGA style monitors, but *not* VGA or
SVGA monitors).

    A Second Sight board plugged into the Apple IIe would allow
you to drive a VGA/SVGA monitor, although the board isn't well
enough supported to function in an Apple IIe (it doesn't support
Double-Hi-Res for one thing, and there are no programs that will
run on the IIe and recognize the SS card natively).

Mitchell Spector
spec@vax2.concordia.ca