🚀 go-pugleaf

In article <5678@batcomputer.tn.cornell.edu>, braner@batcomputer.tn.cornell.edu (braner) writes:
> []
> 
> In a flyer from Priority One Electronics (came with the August BYTE)
> there's an ad for two VGA monitors, a mono one for $150 and a color one
> for $460.  The former is claimed to work with "50 to 70 Hz refresh",
> the latter 60 to 70.  The mono one has white phosphor and supports
> 64 shades of grey.  Both are supposed to display ALL the VGA resolutions,
> up to 720 by 400 text and 640 by 480 graphics.
> 
> Question is: can either of these (or other VGA monitors) be used on
> the ST, perhaps for BOTH the ST hi-res and med-res (and lo-res?) modes?
> What would it take to connect them?
> 
> Any PS/2 experts out there?  (On this newsgroup? Nyaaa...)
> 
> - Moshe Braner

I would not call myself an expert on PS/2s, but I do know more than
a lot of folks when it comes to VGA adapters and monitors -- the VGA
monitors (not the multisync ones but the real PS/2 clones) are fairly
tightly coupled to a 31 KHz horizontal frequency and a vertical rate of
50-75 Hz (depending on the horizontal and vertical sync polarities).

I think that matches the hi-res mono monitor pretty closely (and both
are analog, so a fairly simple cable should be all you need to tie the
mono monitor into an ST), but the color monitor runs at the old CGA
standard frequencies (much lower, 16 KHz or thereabouts, I think) so it
would require a real multifrequency monitor.  And in that case I think
you have to switch the mono monitor sense line to "confuse" the computer.

Oh well,

Charles Marslett
VGA/EGA BIOS whiz
STB Systems, Inc.  <-- apply standard disclaimer here!
chasm@killer.dallas.tx.us