Nekochan Net

looking in the comments of mozilla 1.3a release

i saw this

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If your monitor supports sync-on-green, any 13W3-to-VGA adapter will work. You might have to set the nvram variable sync_on_green to sync_on_green=y, however.

Posted by Marko at January 29, 2003 03:43 PM
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My question is, if there's a way to set a variable for sync on green
it is logically possible to use another type of sync by setting this to no
which other sync is availaible on sgi

I think there isn't, SOG is kind of trade mark thing with SGI.

All sgi machines since atleast the indy also output seprate sync and combined (h+v) sync to different pins look up the 13w3 pinout on the indytech page at http://www.reputable.com/indytech.html#Graphicsboards.

Using the correct adaptor from http://ultraspec.com/pcatalog.asp?dID=100100300&pID=1395-SGI will allow you to drive a non sog monitor (you can also make your own adaptor, if you are any good with a soldering iron).

You may get a greenish tinted screen when using the adaptor, you can try either adjusting it out on you monitor, or if you have a o2 or newer (it may work on an older machine, haven't tried yet) you can try setting sync_on_green to no.

I forgot one thing, the adaptor may confuse your monitor if you have a PnP monitor, just power off the machine and monitor then plug the monitor in after you turn both on. If that fixes it you need to try a different monitor, most PnP monitors work, just some early ones get confused easily (or just get a non PnP monitor).

The thing with most of the SGI monitors is they can support the H+V sync but taht doesn't mean that they actually have it connected up to make use of it. There are plenty of them that just have the 13W3 and will only support the SOG becuase they just don't have those wires connected up.

You could actually remove all of those pins from the inside of your 13W3 connector and still have it work fine in most cases. Those pins are there mainly for legacy stuff.

Has anybody tried this and succeeded?!? I have just tried to convince my Octane to play ball by going into the PROM and 'setenv sync_on_green no' but to no avail.... when I click on done, nothing unusual happens and I can still see the picture perfectly on this ol' SGI monitor (going into the PROM reveals that sync_on_green is no longer set to any value)

The attraction of using the 19-inch diamondtron sitting next to me is too great!!!

All workstations to come out of SGI with 13w3 connectors starting with the indy (and possibly the indigo) and actually puts the sync signal on thost extra pins (no matter what you set). No SGI monitor (I know of) acutally uses them, but they do work. I'm not sure why they would be there for legacy reason, SGI used 3 bnc connectors before they started to use 13w3 on the Indigo.

As for the sync_on_green prom varible I done some research and I think it dosen't exist on any machine or does anything usefull (oops). I still think there is a way to disable sog on newer machines, but I'm not sure how at the moment...

You do not need to disable sog to use the seprate sync signals, but you do need a special 13w3 to HD15 adaptor (all of the ones I know of are wired for Sun, except the one I pointed out in my previous post). It is no longer true you need a sog monitor to use your SGI workstation. However, you may have some problems with green tint, but that can be fixed if your monitor has color adjustment, or if you can figure out how to turn off sog.

That's correct; the Indigo had 13w3 on Express graphics (XS/XS8, XS8Z, XS24, XS24Z, XZ, Elan) and VGA HD-15 on Entry. Express on Indigo used the sync pins in the same manner as on Indigo2.

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Ok... Now my head is spinning....

FYI, setting sync_on_green worked for me:

Octane (250MHz R10k, 512MB EMXI - got it for a steal - $300)
Sun-wired 13w3-vga
Sony SDM-M81 18" TFT

Now I got a quite usable machine to complement my r5k and r10k O2s.