[Sunhelp] SGI + Sun Monitor

[James Lockwood]

On Mon, 10 Jan 2000, Bjrn Ramqvist wrote:

> I have no idea about IBM.

Older IBM's use sync on green.  Some recent ones use seperate syncs.

> So, practicly, my Indy can do 1280x1024 by 76Hz which would satisfy my
> wonderful Sun (Sony) GDM-20D10, but it won't "sync on green". Instead I
> must find myself a SGI (Sony) GDM-20D11 to get the picture working.
> Yes, practicly I could modify my GDM-20D10, but that renders my
> Sparcstation 5 headless. :-(

It's fairly easy to pull out a sync signal and send it to the monitor, but
the green level of the picture will be off due to the fact that the
monitor misinterprets the sync portion of the green signal as additional
green.  This screws up automatic brightness correction in much the same
way that Macrovision does on VHS tapes.

> What's more interesting though, is the fact that I can run a DEC (Sony)
> VRT19-HA on this baby without problems. :-)
> Those monitors were usually found running on either middle- to high-end
> graphics capable VAXstations and DECstations, or on moderate graphics
> capable Alphastations. (like the one sitting on my desk here at work)

Indeed, many DEC and IBM monitors of the era can handle a variety of syncs
without trouble.  The IBM 6091 can handle sync on green (as used by SGI,
HP and IBM), composite sync (Sun) and seperate sync (PC's).  Great monitor
to have on the test bench.  Heck, the 6091/23 makes a good bench all by
itself (weighing in at 105lb).

-James