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From: psrc@pegasus.ATT.COM (Paul S. R. Chisholm)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Can you connect a VGA monochrome monitor to a CGA card?
Summary: no
Keywords: VGA, CGA
Message-ID: <4267@pegasus.ATT.COM>
Date: 23 Nov 89 06:40:10 GMT
References: <1643@aipna.ed.ac.uk>
Organization: AT&T Bell Laboratories
Lines: 34

In article <1643@aipna.ed.ac.uk>, jlb@aipna.ed.ac.uk (John Beaven) writes:
> I have recently got hold of a cheap monochrome VGA monitor (Alcatel) and I 
> have been told that it is possible to connect it to a CGA card (of course, 
> giving CGA picture quality).
>...
> Another story I heard was that this was impossible.

That's the one I'd believe.  CGA (and EGA) adapters send a "digital"
signal; for every pixel, each "color" is on or off.  (The definition of
a color gets a little tricky; CGA has red, blue, green, and "intense",
for four "colors", and 2**4 = 16 colors.  EGA has reg, blue, green,
intense red, intense blue, and intense green; six "colors", and a
palette of 2**6 = 64 colors.)  VGA color monitors have only three
colors (red, blue, and green), but each color can be at 2**6 = 64
levels of intensity, for a palette that can choose between (2**6)**3 =
256K colors.  I think VGA "monochrome" (really gray scale) monitors can
display 2**6 shades of gray.  You could use that to substitute for
colors, but hardware to translate digital video to analog video would
probably cost than a VGA board.

Yes, there are multi-frequency monitors that can accept both analog and
digital signals, beginning with the original MultiSync.  I don't think
that's what you've got.

In my humble (yeah, right:-) opinion, the best way for you to use the
monochrome VGA monitor would be to buy a VGA card.  They're not that
expensive, and you can trivially upgrade to color as soon as you can
afford a color VGA monitor.

> John Beaven, email: jlb@aipna.ed.uk.ac

Paul S. R. Chisholm, AT&T Bell Laboratories
att!pegasus!psrc, psrc@pegasus.att.com, AT&T Mail !psrchisholm
I'm not speaking for the company, I'm just speaking my mind.