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Forums -> Multiple monitors -> dual monitors and KVMs
Mountain Bikn' Guy   2003-10-18 04:00
After many months of effort and expense, I finally have a good dual monitor extended KVM setup. Here are the details and some history.

I have 3 computers located about 100 feet from my desk (in the garage). Each has a dual monitor card (Appian Jeronimo Pro, PNY GeForceFX, & Matrox G550). I use 2 Viewsonic VP181b flat screens (analog), each at 1280 x 1024. I also have a special mouse (Contour Rollermouse USB) and a special keyboard (IBM Trackpoint PS/2). All of these factors made it almost impossible to find a good KVM solution. I could list many pages of what doesn't work. I'll give a few examples.

I tried the CompuCable Dual Monitor 2-Port PS/2 KVM Switch (KVM-201DUO) ($189) and the video resolution was very poor. Text was fuzzy and hard to read.

BTW, I extended the video by using 2 special coax VGA cables (100 ft long) from

For a while I was using 2 Belkin KVMs. They have good video quality and they support audio. However, switching computers from 100 ft away is very problematic -- the keyboard hotkeys only switch the KVM that is plugged into the keyboard. The only way to switch the KVM for the 2nd monitor is to use another keyboard (and another 100 ft PS/2 extension cable). On top of this, the USB to PS/2 converter on my mouse caused some compatibility issues that finally became too annoying. So I looked for a better solution.

Belkin recently announced their new dual head KVM (OmniView™ SOHO Series 4-Port KVM Switch with Audio). The video resolution looks to be best in class at 2048x1536@85Hz. The audio is also unique in this class. So I made the purchase. (Beware -- this model takes special cables. All my existing Belkin cables wouldn't work and cables can be a big investment.)

Unfortunately, it wasn't a simple deal to get this new KVM working. It isn't compatible with special keyboards, for one thing. And it won't operate unless a keyboard it likes is plugged into the correct USB port on the KVM. I didn't want 2 keyboards on my desk (why upgrade to this KVM, after all?).

A key part of my solution was the X-keys stick ( It can be put in a special mode to work just like a USB keyboard. I programmed it with the hotkeys for the KVM and plugged it into the KVM's keyboard port and the KVM liked it. However, I needed it 100 ft away at my desk. I used a Cat5 USB extender (Aten UCE50, $100) and that worked.

Next I need to hook up my real keyboard and mouse. I used a Y-mouse® Adapter for USB to connect my Trackpoint keyboard. My Rollermouse was already USB. Now I needed to extend these 100 ft also. I used this product ( that is also a 4 port USB hub. I connect my Trackpoint and my rollermouse to it and ran CAT5 for the 100 ft distance.

The solution works incredibly well. I tried a lot of things over many months. Even the $3000 high end "solutions" were not adequate.

But this solution does everything and it does it well. The video quality is good. I have audio on all computers. I can switch computers using a single button (on the X-keys). All my pointing devices work (I even have a wheel mouse plugged into the Rollermouse). Even the Trackpoint works. I no longer have weird mouse compatibility problems.

I wasted a lot of money on solutions that didn't work (and I have a few decent single monitor KVMs that I now need to sell). But the final solution is the best that can be done and it costs a small fraction of what the specialty vendors charge for their KVM solutions.

I hope this helps others who want a good dual monitor EXTENDED KVM solution with audio and all the bells-and-whistles.
ecarlson   2003-10-18 13:28
Cool. Thanks for all the information. Hopefully I won't have to do anything like that any time soon, but if I do, at least I have the info I would need.

Good thing you didn't have to go 110 feet :-)

- Eric
Mountain Bikn' Guy   2003-10-19 01:24
That's a good point. At distances over 100 ft, the video cables get much more expensive. does have video cables that can go to 250 ft (and longer I think). But I would probably have gone with a KVM extender over CAT5 for the video if my distance was much greater. For video over CAT5, plain old CAT5 is the best (not CAT5e or CAT6e, etc.). I actually ran CAT5 beside my 100ft video cables in case I ever switched to this solution.

In my experience, the USB extension would possibly prove more difficult than the video. There seem to be fewer choices at this time. The one I used (Aten/IOGear UCE50) can be found as cheap as $80, but it is limited to about 100 ft. I found one other at CablesDirect that goes to 150 ft for $125. All the others are much more expensive, and many of them still have similar distance limitations. BTW, one engineer mentioned to me that CAT5e and CAT6e might be better for USB extension, but I didn't research this as deeply as I did the video over CAT5 question.

Dave   2003-11-23 07:32
Here's an update to my prior post on a couple points:

1. Not all my mouse compatibility problems went away. There is a really weird issue with Directory Opus software when using any Belkin KVM(don't know about other brands -- could happen with them too).

2. The dual head Belkin KVM will not support multiple USB extenders. It doesn't provide enough power for them.

3. CAT6e cable seems to work better with the USB extenders, but CAT5 works too.

4. I don't recommend extending a USB KVM (at the current time) unless you are prepared for a serious effort or you are a professional. I'm sure things will improve, but right now it reminds me of the things I used to have to do before Plug-n-Play and Windows drivers were standardized. It is amazing how one part works with one othe part, but neither works with a 3rd part, and one or the other conflicts with yet another part. It was a bit of a nightmare.

It turns out that not all is working as well as I initially thought. It's still somewhat problematic.
ecarlson   2003-11-23 09:00
Thanks for the update. Please let us know if you solve any of the new problems.

- Eric
arourke   2006-02-26 05:08
There seems to be a new alternative to KVM. Check out Matrox Extio F1400.

For an explanation of the technology (including comparisons to KVM), see the Extio (RGU) technology guide.
ECarlson   2006-02-26 12:56
Looks cool, though I'm sure it's not inexpensive, and it looks like it only works with a single PC, so if you want to access multiple remote multi-monitor systems, it probably isn't the option for you.

- Eric,
ramonaguayo   2006-11-19 23:35
Im preparing 13 computers in rack and with extension that goes from 50 to 100 feet, thanks for your advise
GOD bless you
Darrylle   2010-07-09 20:02
Thanks for the heads-up, but I'm still not entirely clear.

I have a single monitor output KVM (2 x pc monitor cable IN, 1 monitor OUT).
I have a 2 pc's, 1 with 2 monitor's the other with one.
I was wanting to ditch one monitor, kb & mouse and then use BOTH monitors on EITHER pc's (when switched) so that I can slide a window from one monitor over to the other (as it is now on 1 pc).

Is there any way this can be done with a 'single monitor output' KVM? E.g. VGA splitter into the single KVM output?

Thanks for any advice.
ecarlson   2010-07-10 03:01
No, you need a dual monitor KVM, unless you are using something like the Matrox DualHead2Go to connect the monitors to the single-monitor KVM, but I'm not sure how well that unit would work with a KVM, and it would have limitations compared to a dual monitor KVM.

You could also hook up everything to only one computer, then remote into the other computer with a multi-monitor capable remote program, like RAdmin, or if the second computer has Windows 7 Ultimate or Enterprise, or Windows 2008 R2, then Remote Desktop from the client PC (using the latest client version) should support both monitors well. With older versions of Remote Desktop host, you can use the /SPAN option on the client. I don't know if any of the versions of VNC (usually free) support multi monitors: It's been about a decade since I've used any version of VNC.

- Eric
Darrylle   2010-07-10 21:16

Thanks for that, seems I made a bad purchase then.

I currently Real VNC into the 'server' PC, rather than use it's K/V/M, but as you'll know - you don't get the responsiveness.

Looks like I need a dual monitor KVM.

I've got a dual monitor graphics card in one pc (obviously). Would I need another dual on the 'server' pc in conjunction with the dual KVM box?

Thanks again.
ecarlson   2010-07-11 03:03
If you want to connect 2 monitors, you have to have 2 distinct video outputs to connect those 2 monitors to. If you don't currently have 2 video outputs on the server, you'll somehow have to get to 2 outputs.

There are many ways to get to 2 outputs, but the simplest for desktop computers is usually to use an ordinary dual output video card.

The dual output video card I'm using was something like $19 after rebates, so it can also be the cheapest solution.

- Eric
Shibu   2010-11-06 23:33
I have been using a Belkin DVI KVM switch to switch between my WinXP desktop & a Mac mini for some time with success. I recently upgraded to 2 widescreen 23.3" HP monitors.

Now I use the KVM to switch the keyboard & mouse to switch between the Mac & PC. I use one monitor for the PC & the other for the mac. This works great most of the time. Sometimes I actually want to use both monitors with the PC OR both monitors with the Mac.

How do I do this? Both the PC & Mac support dual monitors. I have seen Dual monitor KVMs but is there a model that will allow me to switch each monitor independently? Rmember most of the time I will be using 1 monitor for the PC & 1 for the Mac. I thought about just using 2 KVM switches but the problem is that many KVM switches will not work if there is no keyboard ot mouse connected & clearly the point of this is to use 1 KM with the two computers. The X-stick mentioned aboved seems to still be available. It just looks kind of ugly. I use a mac keyboard & mac pc & would prefer to keep the aesthetics the same. Maybe I will mount it under the desk.

I think I would prefer a dual monitor KVM that supports independent monitor switching.

Any suggestions?
Kuan   2010-11-10 23:30
The simple solution if you are using VGA connection, you just need to get

1)AdderView PRO 4 port Dua VGA head KVM Switch

2) AdderLink X50 Dual Screen USB Extender.

With this solution you can extend 2xVGA, USB including USB peripheral support & speaker via 2 CAT5 cable up to 50m away.

Forums -> Multiple monitors -> dual monitors and KVMs

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