A KVM switch without ghosting ?

Is there a KVM switch out there somewhere that doesn't result in ghosting in the picture ?

Every KVM switch I have ever used has some sort of ghosting on the video signal that gets to the monitor. This has always stopped me using a KVM switch on my PCs (despite the fact that I would be useful).

I need to use three different machines at the moment (Virtual PC saves me from needing to use about 9 different machines, but I still need these three physical machines). So I went and bought a Belkin OmniView 4 port PS2/USB switch.

I have to say it is better than any KVM switch I have used before from a ghosting point if view. But, it is still there. Thankfully it is faint enough that I can ignore it most of the time, but it is still there and annoys me when I see it.

So, are there any KVM switches out there that don't ghost, or do I have to wait for a new monitor/graphics card and step up to DVI switching ?

fwiw, im using a Belkin OmniView E Series 4 port, and have had no ghosting problems.

Did you use the same cables in all of the KVM switch comparisons? Perhaps it was the cable quality or lengths that was causing/adding to the problem?

I have always used the cables that either came with the switches or where recommended by the manufacturer. In the case of the OmniView that I just bought I am using their recommended cables.

I know it isn't caused by cable length or routing, if I connect unplug the cables from the switch and connect them together without the switch in place the ghosting is gone. The ghosting is the same whichever source PC signal I am viewing.

Like I said, I have seen this issue with every KVM box I have ever used. Some of them weren't "cheap" (just paid over $200 for this one) consumer ones.

Mmmm.. no ghosting here -- Linksys 4-way PS2 KVM switch, with VERY HEAVY (thick) cables..

Maybe they're skimping on cable quality these days -- I got mine several years back.

Cheers

Every single time I've seen ghosting problems on a CRT, the problem has been in the cabling, not the switch.

I had one of those exact same Belkin KVM switches, and I used the high-quality cables for my Windows box (i.e. the GUI) and the normal quality cables for my Linux boxes (i.e. text mode), and had no ghosting.

I got rid of the switch (for other reasons), and I'm now using an iogear two-port switch, which also has no ghosting problems.

What resolution and refresh rate are you running at?

Also, are you using the same monitor (and integrated-to-the-monitor cable) in all of the tests?

-brendan

I am using this cheapie KVM (http://www.tcwo.com/cgi-bin/webc.cgi/st_prod.html?p_prodid=1484&sid=44oBmP0@@MNc7zV) with no complaints. It is only a 2 port model, but the also offer one with 4 ports.

Scott

1024x768 at 100Hz, so hardly pushing it.

I am using the same captive cable on the monitor, have no choice. But when I use just the two cables back to back to connect one PC to the monitor there is no ghosting. The ghosting is caused either by the switch or the connections between the cables and the switch.

I'm not running some big test to compare different switch boxes. I have seen this ghosting with all the switch boxes I have used over the last 5 years or so.

I've had this problem too. The best switch I've found was a Protec out of Canada and the last time I used it I bought the best cables Belkin had to offer (that time I verified that the ghosting problem was made worse by the belkin cables).

Actually, under normal use, I probably wouldn't have noticed, but I do cad work, with tiny black lines on a white background, and it's very apparant there.

I, too, would love to find something that works.

Ghosting is what we see when there are time-delayed copies of the image displayed (at weaker strength) alongside the original image.

These copies are reflections of the original signal from impedance mismatches in the cabling. Shorter cables will reduce apparent ghosting, simply because the ghost images don't have as far to travel as they bounce back and forth between the cable connections.

Gold plated contacts on all connectors will help to minimize impedance across the connections. The proper choice of correct impedence cable (by the manufacturers) can also help, as can cabling with better shielding. Ditto for the KVM switch itself -- better shielding there can help reduce pickup of stray emissions.

Cheers

So if I connect my monitor to my PC using the captive cable on the monitor and the cable that connects the PC to the switch and there is no ghosting, but when I connect the same cables via the switch I get ghosting then it must be the switch rather than the cables ?

http://www.amulethotkey.com/ are the best in the business.

None of the switches seem to have USB support, which rules them out for me as my laptop has no PS/2 ports (unless I also get a PS/2 to USB adapter). They are also one of those annoying companies with no prices on their website.

They ain't cheap.

I also worked with a company from Holland who had built the first digital KVM switch that worked over a single Cat5a or Cat6 cable which was pretty good. Can't remember what they were called though sadly.