The video switch issue, how it turned out

Remember way back when when I was having problems with the KVM and signal loss?
Well, we’re a week and a half later now, and I’ve changed over to a Zonet KVM3112 purchased from NewEgg for a mere $31.00.
This is a nice little KVM. It’s a simple 3″ square box that dangles from the cables that comes with cables already attached to the unit The cables are bound with USB connectors as well, so there’s only one cable going to each switchable device, and the USB connector breaks out at the end.
At the moment I have it between the Mac Mini and my IBM T40 laptop. I’ve tried it also between the laptop and the Shuttle PC I use for Windows stuff, and between the Laptop and the Mac, and in every case, the laptop image has a slight shadow to it, while the other machine is crystal clear.
My guess is that the laptop has a weak-ish video signal on the external port (heck, it was never relaly meant to be a desktop machine like this). I’ve ordered a docking station for it, we’ll see if that has a better signal on it. Even without that, though, this is quite useable.
So, the short answer is “When doing KVM work, get a decent unit, don’t scrounge. They’re not that expensive.” I can pretty well recommend the Zonet 2 port switch – very inexpensive, works exactly as planned, and has the benefit of NOT require an external power supply. It switches VGA and USB signals without a glitch, using a keyboard macro (scroll-lock scroll-lock arrow).
I’m using a Microsoft natural keyboard (these things are getting hard to find – 2 stores I went to didn’t have them – just flat keyboards), and a Logitech USB mouse. Both of these are patched directly into the KVM, and they’re being switched between the laptop and the other system.
Now I just wish I had a 3 port unit 🙂

Dave Shevett


A wandering geek. Toys, shiny things, pursuits and distractions.

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3 thoughts on “The video switch issue, how it turned out

  1. actually, the “poor” signal quality might have something to do with the lack of power supply. there’s some electrical reason for it that i learned way back in television production but no longer remember, but things that split or combine electrical signals often need to be powered in order to ensure a full-power signal on the output.
    otoh, i could be completely off target 😉

  2. Ben sez:
    actually, the “poor” signal quality might have something to do with the lack of power supply.
    I’d agree with that, but for 2 things. The old switch (the Belkin F1DZ102T) had -abysmal- signal quality on every input. The laptop, the mac, or the PC – all of them sucked rocks. And the belkin had an external power supply.
    The other thing is the signal quality from the mac and the PC are now -very very- good, while the laptop has only slight degredation.
    I think you’re right though, that when using a signal splitter, you need to amplify the original signal to cover both destinations, but this isn’t really a splitter, it’s a switch. Each input is still only driving one destination.
    I’d guess you’d get -some- signal loss in the switch itself, but it appears to not be enough to matter.

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