NestorK wrote:
Hi. This is my first post on this board.

I have a two computers (both Pentium IV's running Windows XP) and an IOGear KVM switch. The KVM switch has PS/2 ports for keyboard and mouse, and I'm finding that most new computers don't have PS/2 ports. I'm hoping to find a reliable way to add PS/2 ports to a computer that doesn't have them.

I phoned up IOGear Tech Support and asked if I could just use a USB to PS/2 adapter cable like this one:

http://www.amazon.com/Syba-Adapter-C...sb+ps2+adapter

and was told that it wouldn't work.

I've been able to find PCI cards that allow me to add two PS/2 ports for keyboard and mouse, but PCI slots on motherboards are also becoming rare. Nowadays, lots of motherboards only come with PCIe slots, and my understanding is that you can't use a PCI card in a PCIe slot.

I've not been able to find a PCIe PS/2 port card.

What I have found is a "card" (so to speak) that doesn't use a slot:

http://www.sybausa.com/productInfo.php?iid=799

But I can't say that this "card" would work any differently than the adapter cable linked to earlier. After all, it still connects two PS/2 ports to a USB port just like the adapter cable.

People have suggested a software solution like "Synergy". Apparantly, you load the Synergy program onto both computers, and the computer monitor shows what's going on on both computers depending on where you move your mouse. So, it acts kinda like a KVM switch. I use one computer to run my business and one computer for surfing the net. I like the idea of having the computers physically separated because if I get a virus on my internet computer, I simply format the hard drive and reload Windows XP. I'm concerned that with only this Synergy software, if I get a virus surfing the web, both computers will get infected. With a KVM switch, there's no way a virus can get from my internet computer to my business computer.

Can anyone think of a sure fire way to add PS/2 ports to a computer that doesn't have them so that I can continue using my KVM switch. If push comes to shove, I might just have to buy a new 4 port DVI or HTMI USB KVM switch.

As far as I know, there is only one PS/2 chip
still in production.

Your Syba product (second link), the picture is
intended to show the Chesen USB to PS/2 converter
chip. As far as I know, the Chesen chip is out of
production. Some other (ITE?) chip is being used
now. So Syba might be silently changing over
to the other chip.

When you purchase a PCI to PS/2 card, it still uses
the Chesen. The board consists of a PCI to USB chip,
plus the Chesen USB to PS/2 chip.

If someone made a PCI Express version, it would
consist of a PCI Express to USB, plus a Chesen chip.

The adapter cable, the one with USB on one end, and
dual PS/2 on the other end, the Chesen chip is hidden in
a plastic blob in the middle of the cable.

The Chesen chip contains an 8 bit microprocessor and
ROM firmware. That means the protocol conversion is
firmware mediated. The 8 bit microprocessor is likely
similar to an 8085 running at 12MHz or 24MHz or so.

So they're all basically relying on the same concept,
and just packing a little extra infrastructure around
it as the situation requires. The conversion is
done with USB, and any other card format, just goes
from bus standard to USB, before the Chesen is added
to the picture.

Keyboard protocols are pretty mysterious stuff. Any
mistakes Chesen made in writing their firmware,
those changes would be hard-fought, and they wouldn't
exactly be telling the world what they had to do to
fix them. You can't flash upgrade that chip, and if it
has bad firmware, you have to buy another adapter. Since
the Chesen chip no longer ships, the replacement
chip could have its own firmware issues with converting
certain key sequences. The fact there is a processor
in there, should suggest to you they weren't really sure
what they needed to do, and it was made programmable so
they could deal with "surprises". That's my guess.
And some KVMs, do have weird key sequences for
inline switching.

Paul