KVM switch and monitor issues

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Solved KVM switch and monitor issues

Post by skypilotpete on 24th July 2008, 6:02 am

I recently purchased an ATEN KVM CS-72E switch. I am using the switch to connect 2 computers to an LCD monitor.

This setup works most of the time, but it has a major bug, which I can't understand. For the monitor to recognise either of the computers correctly, I have to have the monitor showing the computer while it is starting up, or else I have problems. The particular problem varies according to the computer. It is a bit complicated, but I'll try to describe it as clearly as possible.

Scenario 1: I start Computer 1, while it is connected to the monitor via the KVM switch. I watch Computer 1 start up, and it works perfectly. Now, while I am working on Computer 1, I start Computer 2 and let it start up without viewing it on the monitor (ie, I do not switch the monitor over to it). Now, when I switch the monitor over to Computer 2 using the KVM switch, I get the message "Analog Out of Range". The only way I can get the monitor to see the computer is to reboot and watch it all the way through startup.

Scenario 2: I start Computer 2 watching it on the monitor via the KVM switch. It works perfectly. Now, while I am working on Computer 2, I start computer 1 and allow it to start up without viewing it on the monitor. I switch the monitor over to Computer 1 only after it has completed its Windows startup. I am able to see the desktop for Computer 1, but the monitor has lost its display settings. It is now displaying at 800 x 600 instead of 1280 x 1040. Once I correct the settings, everything works correctly.

Scenario 3: I start Computer 1, watching it on the monitor until windows startup is completed. I now switch the monitor over to Computer 2, turn it on and watch it through to the completion of Windows startup. Both computers can now be seen correctly and from then on I can switch back and forward between the 2 of them without problems.

Can anyone tell me if this is an inherent aspect of a KVM switch or an LCD monitor? Does an LCD monitor have to actually see the computer while it is starting up to be able to recognise it correctly?

I have tried contacting LG support and ATEN support, without luck so far. LG simply said that "Analog out of range" issues are due to a faulty graphics card and I should replace it. This doesn't make sense, as I never had any issues before I started using the KVM switch.

I haven't had any answer from ATEN.

My setup is:

Computer 1: Pentium 4, 3 gig processor, 2 gig RAM, Windows XP Pro SP2. nVidia Geforce FX 5700. It is on KVM switch 1.

Computer 2: AMD Athlon 1.6gig processor, 1gig RAM, Windows XP Home SP2. nVidia Geforce FX 5200. It is on KVM switch 2. This is the only computer which has shown the problem so far.

Monitor: LG Flatron L1954TQ

I do not have any power saving options activated on my computers. Everything is set to be on all of the time.

Both computers are set at 1280 x 1024 resolution (recommended for the monitor) and at 60 mhz refresh rate. I have also tried them both at 75 mhz.

Both computers have the monitor's drivers installed from the CD that came with it.

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Solved Re: KVM switch and monitor issues

Post by Digitalocksmith on 24th July 2008, 11:55 am

Hi skypilotpete and Welcome to GP!

@skypilotpete wrote:LG simply said that "Analog out of range" issues are due to a faulty graphics card and I should replace it.

Lol.....Dont you just love these tech support guys, god bless em! Cheesy Grin (sparkly

On looking over the specs for the switch at this site here: http://www.directron.com/cs72e.html
One thing did jump out at me which im not sure if you may have looked into yet is the feature: "Auto Scan function to monitor computer operation".

It also denotes a scan interval time of 5 Seconds!

Now im not entirely sure what this means exactly as i admit to not having any experience with the switch in question and it is my belief that the issue you are experiencing is related directly to the switching function and the hardware device itself rather than at the end of either of the computers.

Could the scan function and scan interval timings have something to do with only being functional when the detected port computer has fully booted to windows.......ie Are the software drivers for the device only fully functional at boot completion?

Whats your assesment?


Regards



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Solved Re: KVM switch and monitor issues

Post by skypilotpete on 24th July 2008, 12:54 pm

Thanks for your suggestion. I tried the autoscan function and it only means automatically switching between the two ports - it just goes back and forward between the 2 computers, but doesn't change the problem described.

I am a complete techical ignoramus, but I'm starting to strongly suspect that it is to do with the LCD monitor. I think the monitor needs to be connected to the computer as it is booting up, so that the monitor and computer "shake hands" in some way. Is that possible?

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Solved Re: KVM switch and monitor issues

Post by Digitalocksmith on 24th July 2008, 3:48 pm

Some monitors also support multiple inputs and allow you to switch between those inputs via a knob on the front of the monitor (my new Samsung widescreen LCD supports a DVI digital input and an analog VGA input...and can swtich between those two inputs...Your LG will also support this and so will your video cards so you could try connecting both PCs on each port, switching between the two and see if this helps to alleviate the issue.(ie you could possibly do away with the KVM switch altogether but you would need a keyboard and mouse for each system)

Its not the monitor itself, Its the keyboard and mouse which needs to be registered with each computer.

I did a bit more research into this and apparently, you need to Have each computer selected when booting to ensure that the computer/KVM switch registers the keyboard and mouse, before changing to another computer.

So in a way, your guess is correct....This 'handshake' is apparently needed.

Not sure if this issue would be averted if you were to use individual keyboards and mouse for each system, eliminating the need for this 'handshake' registration.

Guess its just one of those annoying little quirks that you may just have to live with if non of the above work-arounds come to the party!


Good Luck dude

Honored



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Solved Re: KVM switch and monitor issues

Post by skypilotpete on 25th July 2008, 4:00 am

Thanks for your efforts. I have done a bit more playing around, which I suppose I should have done from the beginning.

I have tried connecting the mouse and keyboard directly to the computer, but leaving the monitor unconnected. I then started up the computer, and once it had completed its start up, I connected the monitor directly to the computer. Same issue - Analogue out of Range!

I then tried starting up the computer unconnected to the monitor (keyboard and mouse still directly connected) . I then connected the monitor to the computer using the digital connectors. Still no joy - this time I get the message "Digital power saving mode" and there's no way I can get the monitor to display.

So it seems I just have to accept that I have to have the monitor switched to whichever computer is starting up. This isn't such a hassle in the scheme of things, now that I now what is going on. At least I have learned something about my monitor.

Thanks again for all your help.

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Solved Re: KVM switch and monitor issues

Post by Digitalocksmith on 25th July 2008, 7:12 pm

No probs at all.....your welcome!

Let us know if you find a work-around Awesome (sparkly)


Regards



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