Which OmniView ? there are many variants. Have you tried a different VGA cable from the computer to the KVM ? Not all cables are created equal.
Sometimes (most of the time) you must have the KVM switched to that vintage computer when it first boots or else oddness can occur based on my experience....which is limited 😀

Not KVM related, but I've got a card that incorrectly detects my CRT as mono. I need to run a utility called SMONITOR on startup to force colour mode. Details in this thread:

Tseng labs ET4000AX - no color = problem

Maybe uses the old VGA ID pin setup to detect monitor...

1ID pins set-up
2
34     11   12
4ID2  ID0  ID1
5
6n/c  n/c  n/c   no monitor
7n/c  n/c  GND   Mono monitor which does not support 1024x768
8n/c  GND  n/c   Color monitor which does not support 1024x768
9GND  GND  n/c   Color monitor which supports 1024x768
10GND means connected to ground
11n/c means that the pin is not connected anywhere

I've tried different VGA cables. I was so sure that smonitor was going to work... but sadly it didn't make any difference. It exited as if it had worked but things were still in mono.

There are alternatives to SMONITOR such as TVGAUTIL (also linked in that thread) or COLORON. Worth trying, but feels like a pretty long shot if the first option didn't work.

Which S3 and omniview? I've used a few S3 models with the 2 OV kvms I have (a 2-port and a 4-port w audio) and haven't had this issue, but want to be sure you're not using something outside my usage before I start making some suggestions that could be pointless

It's an omniview pro2. It's an 8 port KVM with PS2 mouse, keyboard and a VGA port for each machine. Model number F1DA108P

Pierre32 wrote on 2022-07-06, 12:05:

There are alternatives to SMONITOR such as TVGAUTIL (also linked in that thread) or COLORON. Worth trying, but feels like a pretty long shot if the first option didn't work.

TVGAUTIL seems to be the archive that contains smonitor. http://files.mpoli.fi/unpacked/hardware/displ … il.zip/utility/ I picked it up from that link.

However the "Color On" utility WORKS!

Brilliant!

Nice!

There is one problem remaining. CLS no longer clears the screen and when I exit something that used a background colour like edit then the screen continues to have the last background colour used.

I'm not sure if that could be fixed as the coloron file does have the source for it. Sadly I don't know any programming at all.

However I don't think it's anything other than a mild annoyance.

Edit : Well what an outcome - running both of the utilities - coloron.com and then smonitor.exe fixes the issue completely as far as I can tell!

So now in my autoexec I'll have coloron, smonitor c, s3black and together all 3 of them will fix my display issues

Glad you have it fixed. I have never had any S3 based card issues with S3 Trio, Trio 64, 64+, 3D, Virge, etc from VLB to PCI with any monitor yet, including CRT and newer LCD but will keep a note and link to this just in case I ever run into it.

It may be the KVM. I've got 5 PCs connected to it. 2 have the mono issue and another detects a VGA connection as DVI-D, so I've had to use an active connector. But all 5 connected PCs are currently working with workarounds.

This trick works for me, but I have a different KVM:
-Switch the KVM to a different pc (even turned off)
-Turn on the pc that detects the monitor as mono
-After a few seconds switch to the correct pc

another alternative could be a VGA EDID emulator? ^^