Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ulowell!tegra!vail
From: vail@tegra.UUCP (Johnathan Vail)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Mono-monitors at colour-adapters ?
Message-ID: <503@atlas.tegra.UUCP>
Date: 15 May 89 15:06:39 GMT
References: <5003@uklirb.UUCP>
Organization: Tegra, Inc., Billerica, MA
Lines: 51
In-reply-to: kirchner@uklirb.UUCP's message of 12 May 89 07:50:36 GMT

In article <5003@uklirb.UUCP> kirchner@uklirb.UUCP (Reinhard Kirchner) writes:

   How can a monochrome monitor be used at a colour adapter ?

   and the rationale behind: How to run programs which insist on CGA, EGA, VGA-
    colour if you only can afford a mono-monitor.

   Till now I see the following possibilities:

   1. Buy or build some kind of 'three-colour-output-to-one-video-input-converter'
      which should consist of some resistors and which transforms the colour
      signals to a shade of grays. If the monitors syncs this could work.

Syncing is the easy part.  The cheap "mono" monitors are TTL.  That
means that the video signal is either on or off (yes, there is the
intense signal that gives you on, intense or off).  Getting one of
these to do shades would be difficult.  Monitors that are designed for
shades are almost as much a color monitors.

   2. Use the mono-monitor at a hercules adapter and convert by software.
      I have seen such converters for CGA->hercules, but not for EGA or VGA.
      Are those existing or for some ( which ) reason impossible?

CGA emulation is slow and will suffer compatibility problems.
Impossible for EGA/VGA since the memory is not directly accessible but
fiddled with different hardware registers.  These cannot be emulated
in software.

   3. Some intelligent graphic adapter could do the conversion by itself.
      I know that VGA-adapters my drive mono-monitors, but
      - does this work even if the software uses a colour mode or must the
	software use the VGA-mono-mode ?

Unknown.  Maybe someone else knows.

      Is there any adapter known which does the conversion for CGA and EGA ?

   R. Kirchner
   Univ. of Kaiserslautern, Germany

I would suggest the Zenith mono-EGA.  It can do 16 shades with an EGA
card for about half the price of a color monitor.

"Do policemen dream?
   ..Yes when they're fast asleep.
 And when policemen dream?
   ..It proves they're fast asleep" -- Robyn Hitchcock
 _____
|     | Johnathan Vail | tegra!N1DXG@ulowell.edu
|Tegra| (508) 663-7435 | N1DXG@145.110-,145.270-,444.2+,448.625-
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