Re: help, RGB

["Ralph Wade Phillips" <ralphp@gcstation.net>]

Hi, Nathan!

Nathan Mates <nathan@visi.com> wrote in article
<51nc0f$aep@darla.visi.com>...
> In article <Pine.SUN.3.91.960916191758.10195B-100000@lo-pan>,
> Cyrus Roton  <croton@ridgecrest.ca.us> wrote:
> >There used to be a device, called "Mappler", which converted Apple
analog 
> >RGB (15-pin) to IBM digital RGB (9-pin). There seems to be plenty of 
> >cards to output Apple RGB and plenty of IBM type monitors at low prices.

> >But how to interface the two???  Does anyone have info on this subject?

	Notice three things:  1) Converts Apple analog RGB to IBM !DIGITAL! RGB. 
I remember the device, altho I can't for the life of me remember anything
ELSE about it ... save that I saw a schematic of such a device in an old
Taxan RGB monitor book.  What the Taxan schemed device did was to weight
the lines somewhat, to rebalance the RGB with the PC's RGBI scheme.

	Worked OK - brown never was much to write home about, but .. <B-)

> 
>    An Apple II is not a Macintosh, especially when it comes to RGB
> video out. Sure, the connectors are the same size, and both say
> they're for Apple analog RGB monitors. But, the GS and most Apple II
> RGB cards put out a horizontal sync signal of 15Khz. Pretty much all
> modern Mac and PC RGB monitors require at least a 30Khz horizontal
> sync signal.

	True, but modern PC RGB monitors aren't digital, either.

> 
>    Also, I think that only the CGA/EGA monitors on PCs had 9-pin
> digital connectors. SVGA is definitely 15-pin analog. (But, that's a
> different 15-pin setup: 3 rows of pins vs 2 for Apples)

	Ayep, save for the analog/digital multiple-sync monitors that were common
during the changeover in the PC world from EGA to VGA.

> 
>    Thus, a straightforward Mac RGB -> [S]VGA converter won't work
> when connected to an Apple II. And if you want to be asking about a
> converter hanging off a Macintosh, you should ask on a Macintosh
> newsgroup.

	But he didn't ask for a Mac RGB -> [S]VGA converter.  He asked for an
Apple Analog to 9pin Digital RGB converter.  Specifying digital kind of
lets out the analog VGA standard, and its derivatives, doesn't it? <B-)

> 
> Nathan Mates
> 
> --
> <*> Nathan Mates http://www.visi.com/~nathan/      <*>
> # What are the facts? Again and again and again-- what are the _facts_?
> # Shun wishful thinking, avoid opinion, care not what the neighbors
> # think-- what are the facts, and to how many decimal places?  -R.A.
Heinlein

	Dem's de facts, boss!  (To misquote Kingfisher)

	RwP