KVM switch box for old and new computer \ VOGONS

KVM switch box for old and new computer

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First post, by fractal5

Posted on 2014-07-06, 19:37

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What KVM switch box can handle both serial, PS/2 and USB?

Now you're probably thinking, why not just use an adapter? And sure, I've tried that. It doesn't work.

I haven't bothered to look into the details, but when the signal goes through the switch box, e.g. using an USB mouse on a PS/2 switch box, you use one adapter from USB to PS/2, and then a PS/2 adapter to USB to connect it to the modern computer. This doesn't work. Yes, even when the adapter is an expensive, active type that doesn't just rewire the wires like the cheap ones do.

What also doesn't work is this: You use one adapter from USB to PS/2, then one from PS/2 to serial, going through the KVM box, this breaks it. It only works on machines that actually accept PS/2, it seems. I don't know why.

Is this a limitation in the particular KVM switchbox I'm using, or a limitation in something else?

What kind of KVM switchbox do you guys use when you have one monitor for both your modern computer and one for your old system?

Reply 1 of 8, by ElectricMonk

Posted on 2014-07-06, 19:44

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I used to have a KVM that did all that, but it was many moons ago (10 years or so). You might be able to find one, but the newer ones sacrifice serial and PS/2 for USB and HDMI (and maybe DVI). Try a local computer repair shop, NewEgg, or even Ebay.

Reply 2 of 8, by Unknown_K

Posted on 2014-07-06, 20:30

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Belkin had some that did serial + ps/2 and of course some that do ps/2 and USB, but I never seen one that did all 3.

Collector of old computers, hardware, and software

Reply 3 of 8, by fractal5

Posted on 2014-07-06, 21:20

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The solution to the problem doesn't have to be in the form of a KVM switch box, some solution that uses certain kinds of adapters are also possible.

Reply 4 of 8, by Jorpho

Posted on 2014-07-07, 15:13

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fractal5 wrote:
What also doesn't work is this: You use one adapter from USB to PS/2, then one from PS/2 to serial, going through the KVM box, this breaks it. It only works on machines that actually accept PS/2, it seems. I don't know why.

The question is entirely unclear to me. What exactly are you trying? Does your mouse work properly if you remove the KVM and just unplug it manually?

If I'm not mistaken, some older motherboards will not properly detect a PS/2 mouse unless it is plugged in when the computer boots. If you are having trouble using the KVM with ... whatever it is you're using, try leaving it switched to your older computer when you turn it on.

Reply 5 of 8, by fractal5

Posted on 2014-07-07, 17:32

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Jorpho wrote:
fractal5 wrote:
What also doesn't work is this: You use one adapter from USB to PS/2, then one from PS/2 to serial, going through the KVM box, this breaks it. It only works on machines that actually accept PS/2, it seems. I don't know why.
The question is entirely unclear to me. What exactly are you trying? Does your mouse work properly if you remove the KVM and just unplug it manually?

If I'm not mistaken, some older motherboards will not properly detect a PS/2 mouse unless it is plugged in when the computer boots. If you are having trouble using the KVM with ... whatever it is you're using, try leaving it switched to your older computer when you turn it on.

This is what I want and what I'm trying:

One PS/2 keyboard, one USB mouse, one monitor.

The switchbox only accepts PS/2 input.

PC 1 takes only PS/2.
PC 2 takes one PS/2 and USB.

The USB mouse gets converted to PS/2 as it enters the KVM switchbox.

PC 1 has no problems with this.
PC 2, accepting only one PS/2 needs to use USB.

When I try to use an adapter for converting the PS/2 signal back to USB, even an expensive active adapter (which works in other situations), it doesn't work on PC 2.

Reply 6 of 8, by Jorpho

Posted on 2014-07-07, 18:24

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fractal5 wrote:
PC 2, accepting only one PS/2 needs to use USB.

Shouldn't "the one PS/2" work with a PS/2 splitter that allows you to plug a PS/2 mouse and keyboard into the same PS/2 port?

Reply 7 of 8, by Unknown_K

Posted on 2014-07-07, 19:41

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If you just want to use a USB mouse you can get an adapter from USB to PS/2 that comes with older Microsoft USB Optical mice and a Belkin KVM. I use that method for general computing in my lab where I have various era machines on the KVM some pre USB.

Collector of old computers, hardware, and software

Reply 8 of 8, by fractal5

Posted on 2014-07-08, 00:33

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Jorpho wrote:
fractal5 wrote:
PC 2, accepting only one PS/2 needs to use USB.
Shouldn't "the one PS/2" work with a PS/2 splitter that allows you to plug a PS/2 mouse and keyboard into the same PS/2 port?

Good point. 😀

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