Until recently I had two electronic 4 port KVMs feeding a 4 port
mechanical KVM. I had my Sun going directly to the mechanical KVM,
only using the video part, I would just use the directly connected
keyboard when I selected sun on the switch.

I bought (used) two 8 port Apex KVMs. I figured, I'd chain one off the
other and only use them.

They work fine with my linux systems, one of which I know is 1024x640.
But even when I set my sun to 1024x640 at 60 Hz it gives a blank screen
when I go through the Apex switch.

Any idea why? Any idea how to overcome?

I am trying to buy a sun to PS2 adapter, if it is a matter of some pin
being different maybe that will fix it, otherwise I have to reinstall
my mechanical switch...

In article <1128017214.849444.55340@g43g2000cwa.googlegroups. com>, "sqrfolkdnc" <carey.schug@gmail.com> wrote:
>Until recently I had two electronic 4 port KVMs feeding a 4 port
>mechanical KVM. I had my Sun going directly to the mechanical KVM,
>only using the video part, I would just use the directly connected
>keyboard when I selected sun on the switch.
>
>I bought (used) two 8 port Apex KVMs. I figured, I'd chain one off the
>other and only use them.
>
>They work fine with my linux systems, one of which I know is 1024x640.
>But even when I set my sun to 1024x640 at 60 Hz it gives a blank screen
>when I go through the Apex switch.
>

Older Sun cards only do Composite sync.
This switched around the late FFB timeframe.

Even if you have a newer card, many Sun res's are only
composite, as well.
Sometimes the switchers get confused by this.

But most of the 60Hz ones a Separate Sync, more like A PC.


Oh, also, make sure you don't use an SGI 13W3 to BNC cable.
They are different.
And old Sun version only have 4 wires and only support
Composite sync, as well.
(so a new card using a Sepatate resolution will fail on an
old 4-wire adapter/cable)



>Any idea why? Any idea how to overcome?
>
>I am trying to buy a sun to PS2 adapter, if it is a matter of some pin
>being different maybe that will fix it, otherwise I have to reinstall
>my mechanical switch...
>

Thanks. I know the SGI 13w3 adapters are different, I wish I had one
since I also picked up an indigo 2.

I found I missed one test before. The ultra 5s do switch video in the
Apex, although trying to put them through the 2 port Sun KVM fails
(that's ugly, anyway, 13w3 adapters going in and out of that switch. I
should be receiving a sun-to-pc adapter, I wonder if that will help.

In article <1128548596.532753.327420@g47g2000cwa.googlegroups .com>, "sqrfolkdnc" <carey.schug@gmail.com>
<4342b50b$0$223$bb4e3ad8@newscene.com> wrote:
>Thanks. I know the SGI 13w3 adapters are different, I wish I had one
>since I also picked up an indigo 2.
>
>I found I missed one test before. The ultra 5s do switch video in the
>Apex, although trying to put them through the 2 port Sun KVM fails
>(that's ugly, anyway, 13w3 adapters going in and out of that switch. I
>should be receiving a sun-to-pc adapter, I wonder if that will help.
>

What graphics card are you using ?

Thats a good question (what graphics card are you using), I only tried
it with two computers, an SS20 and an ultra 1, and maybe only with them
going through the 2 port kvm. I guess I need to retest, more carefully
and keeping records of what I test. My various second hand computers
have a variety of frame buffers....I don't know if I would be able to
identify them all, I remember noticing that at least one was a 3rd
party. The latest SS20 has a double wide FB that takes up 2 sbus slots.

In article <1128981666.905288.68100@g49g2000cwa.googlegroups. com>, "sqrfolkdnc" <carey.schug@gmail.com>
<1128548596.532753.327420@g47g2000cwa.googlegroups .com>
<4344f83f$0$251$bb4e3ad8@newscene.com> wrote:
>Thats a good question (what graphics card are you using), I only tried
>it with two computers, an SS20 and an ultra 1, and maybe only with them
>going through the 2 port kvm. I guess I need to retest, more carefully
>and keeping records of what I test. My various second hand computers
>have a variety of frame buffers....I don't know if I would be able to
>identify them all, I remember noticing that at least one was a 3rd
>party. The latest SS20 has a double wide FB that takes up 2 sbus slots.
>

OK this stuff is all old enough to be composite (4-wire) sync only.
Even the "horizontal" UPA slots (like the Ultra1) are still composite only.
The transition occured around the time they switched to vertical
UPA slots (late FFB/vertical early FFB2).
Anything PCI is more like a PC, and handles both, I believe.

So make sure the switch handles composite sync.
Maybe it's an option (setup or jumper inside).

Oh, and I'm assuming that you are still connecting to the same
monitor that used to work OK, and not a new flatpanel
or something. Or at least the a direct connection works OK.

Also, if you are using some adapters for the switch, just cable up
all the adapters without the switch, and make sure the cabling is OK.

If your adapter is 13W3 to BNC (4-wire) hook the sync up to the
hoizontal sync of the switch.