PS/2 KVM switch

[NestorK]

Hi. This is my first post on this board.

I have a two computers (both Pentium IV's running Windows XP) and an IOGearKVM switch. The KVM switch has PS/2 ports for keyboard and mouse, and I'mfinding that most new computers don't have PS/2 ports. I'm hoping to finda 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/2adapter cable like this one:

http://www.amazon.com/Syba-Adapter-...d=1391176400&sr=8-10&keywords=usb+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.

 

[Flasherly]

I'm

hoping to find a reliable way to add PS/2 ports to a computer that
doesn't have them.

-
The practical way to make that approach is through USB. From USB your
options are the widest possible. I suppose I'd have used converters
for PS2-to-USB at some point, although better in this case, in my
opinion, to go with the flow and stick within current standards, as
USB is presently king of the hill over the I/O realm of devices.

The PCI thing you mention is partially true, insofar that fewer slots
are available. Of course they're not going to cut their own throats
with PCI-E and game-boys willing and ready to shell out on $200+
graphic cards. Practically the only thing left with mass appeal to
ostensibly computers with power and the balls to do it: to render them
into an idiocy of segmented appeal games hold;- the rest are migrating
to gadget tablets that for nicely fitting into a purse always on the
run to conditionally shop. Same goes for PCI, no throats bleating
just to be cut today, not with another valid computer marketing
segment, such as hi-end PCI soundcards from musical reproduction to
recording purposes, among others, what few odds and sundry ends are
adaptable to PCI. Without doubt, the greater MB purchases by far go to
people with simply an aim to bring up the computer on the internet,
without much interest in expanding on them;- and the sales are a
horror of that reflection, as droves have migrated to such as
chromebooks and whatever [all] else similarly offered: New and
Improved, Better, and, only if you act now, Idiot Proof: Your Dream
Come True. And that's totally ignoring the business segment purchasing
computers.

 

[Paul]

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-...d=1391176400&sr=8-10&keywords=usb+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

 

[Greg Berchin]

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-...d=1391176400&sr=8-10&keywords=usb+ps2+adapter

and was told that it wouldn't work.

I have been using one of these,
http://www.amazon.com/Keyboard-Adapter-Retail-Package-Exclusively/dp/B0064TKPNI/ref=sr_1_81,
for years with an IOGear KVM switch ... successfully.

YMMV.

 

[NestorK]

Greg:

So, you just plug the adapter cable into ANY? USB port on your computer and plug the KVM cable for that computer into the PS/2 ports on the other end of that adapter cable and it works?

 

[Greg Berchin]

So, you just plug the adapter cable into ANY? USB port on your computer and plug the KVM cable for that computer into the PS/2 ports on the other end of that adapter cable and it works?

Yes, that has been my experience. Currently I have it set up on a computer
running XP, but I have had similar success with Vista and 7. It is connected to
an old IOGear MiniView KVM switch.

I can only vouch for that particular adapter (with the black USB plug and silver
wires). I haven't tried any of the others.

 

[Flasherly]

I can only vouch for that particular adapter (with the black USB plug and silver
wires). I haven't tried any of the others.

I've have troubles at times adapting a PS2 keyboard with USB adaptors
(also the couple oddball keyboards scenarios even though perfectly
pair-mated to a PC's I/O ports). Wouldn't consider anything but a USB
keyboard now. (Love an excuse to buy a top-notch $100+ gaming keyboard
off newegg on half-price sale. ...my Focus keyboard is one tough old
tank.)

 

[Paul]

Yes, that has been my experience. Currently I have it set up on a computer
running XP, but I have had similar success with Vista and 7. It is connected to
an old IOGear MiniView KVM switch.

I can only vouch for that particular adapter (with the black USB plug and silver
wires). I haven't tried any of the others.

My only word of warning would be, the silent change over from
the old design, to a newer design. The Chesen chip used in the old
design, is out of production. There is a second chip of similar
design, might even be footprint compatible. What we don't know, is
if the firmware that manages the thing, has the same fit and finish.

Paul

 

[NestorK]

OK, lets say I try using a USB to PS/2 adapter cable and it doesn't work. In that case I'd be likely to tell myself that there's no standing in the way of progress and both PS/2 ports and PCI cards are a thing of the past. In that case, I'd probably end up buying a 4 port USB KVM switch.

The question is: Do I buy one with DVI, HDMI or VGA video input ports?

I want to be able to watch videos in HD on a 1080P TV set or computer monitor, and I was told that VGA theoretically can handle High Definition video.The other thing is that there will ALWAYS be VGA ports on video cards because of the huge installed based of business computers that don't need HighDefinition video to do word processing, spread sheets and other business applications.

I understand that if I go with DVI or HDMI, I can convert to the other withjust a cable adapter. But, if I do go with VGA, does that pretty much rule out watching videos online in High Definition?

 

[Paul]

OK, lets say I try using a USB to PS/2 adapter cable and it doesn't work. In that case I'd be likely to tell myself that there's no standing in the way of progress and both PS/2 ports and PCI cards are a thing of the past. In that case, I'd probably end up buying a 4 port USB KVM switch.

The question is: Do I buy one with DVI, HDMI or VGA video input ports?

I want to be able to watch videos in HD on a 1080P TV set or computer monitor, and I was told that VGA theoretically can handle High Definition video. The other thing is that there will ALWAYS be VGA ports on video cards because of the huge installed based of business computers that don't need High Definition video to do word processing, spread sheets and other business applications.

I understand that if I go with DVI or HDMI, I can convert to the other with just a cable adapter. But, if I do go with VGA, does that pretty much rule out watching videos online in High Definition?

If you check the Wikipedia articles on DVI or HDMI, they'll
give you some idea on resolution limits there.

Worst case, single link DVI does 1920x1200 @ 60Hz with reduced blanking.
Which is slightly more than HD. LCD monitors support reduced blanking,
because they have no "beam" like a CRT used to have, and can go from
right to left (retrace) in no time at all. The old CRTs, needed a blanking
interval for moving the beam. The tightened up format for the signal,
means a higher resolution can be sent.

I think VGA on video cards, has done 2048 or 2560, in other words,
a 400MHz DAC spans the region of interest. In terms of settings,
the VGA video card can then do the 1920x1080 you want.

The question then comes, about propagation characteristics,
cable length, and "effects".

VGA is analog. Every defect in analog transmission (reflections,
crosstalk, image softening with distance) comes into play. At least
on the old CRT monitors, the higher the resolution you selected,
the more you could see things like ghosting, which could
either be a connector effect (reflections) or something
to do with cabling.

When a KVM handles VGA, it might not necessary have the same
bandwidth spec, as the 400MHz DAC in the video card. Generally,
it's inferior to that. The KVM should indicate, what maximum
resolution you could use, due to the analog bandwidth limitations
through the KVM video path.

OK, so what happens with digital transmission ? No reflection
effects, at least at first. When the cable gets long enough,
the digital transmission error rate is no longer zero,
and speckles of colored snow show up. If the cable is made
longer, the amount of snow increases. Eventually, the monitor
loses sync, and if a super-long cable is connected, you'd
get something like the blue "loss of signal" type screen
(or the OSD flashes some message up on the screen).

The KVM needs to "regenerate" the signal. So digitally, it doesn't
do much with the signal. If it sees a 1 on the input cable, it
puts a 1 on the output cable. It shouldn't have an issue with
bandwidth, unless the chip used inside, is incompetently made.
You check the specification of the KVM, to see which DVI or HDMI
standard it is compliant with, to understand what limitations
it might have. For example, early generations of digital video
run at a "clock rate" of 165MHz, whereas a later one does 340MHz.
These rates affect the max resolution the cable carries. As
the rate goes up, the max length of cable might come down.
So if you sent a signal to an Apple 30" Cinema display, perhaps
the cable you could use wouldn't be as long as if you were driving
some 1024x768 display with the same KVM. That's the impact of the
cable, on the ability to get the digital signal through the
cable, interference free. As long as you're not seeing snow
though, the image is "perfect". Unlike with VGA, where even
a zero length cable, might not look good. The KVM might make
a mess of a high res VGA signal, and the companies that
make KVMs aren't exactly oozing a sense of ethics and fair
play when they sell stuff.

So if I was a gambler, and wanted to improve my odds, I'd go
digital. After reading up, on what people get away with,
when buying cabling for DVI or HDMI. While it's possible to
buy additional hardware to improve any situation, most people
just want a KVM plus <limited_cable_length> to work without
additional outlay of cash. The customer wants to pay $80
for their KVM, and the KVM maker is determined to make poo
for $80. Your job is to catch them, by reading the reviews
for the product, before you buy it. And so the battle goes.
Part of the battle is specs, and part of the battle
is detecting honesty.

My reference to "incompetently made", I should expand on that
a tiny bit. When DVI first came out, the 165MHz so-called
"clock", refers to the pixel clock. The byte of data for
each pixel color, is transmitted serially. The actual cable
rate is 1650MBaud. Early GPU chips, some of them (incompetent)
could only do 1350. The GPU manufacturer, would then artificially
limit the resolution options in the video card driver, to hide
what they'd done. The thing was, when that flavor of I/O
came out, it was intended for 622 meg operation, and over
a period of a couple years, the chip makers were able to
push that several times over. But at least a few GPU models,
were caught with their pants down, on the bandwidth required
to send the digital signal (pad driver). And that's the
incompetent part. If the video card said "I am compliant with
DVI spec 1.0" or something, that would have been a lie. If
there was an organization that had been certifying DVI devices,
it would have rejected those products, when they were examined on
a digital scope with eye diagram capability (Tektronix).
I'm hoping, that just about any company making chips
like that today, won't be doing that, and all the chips
will meet their spec. Doing 340 on HDMI is pretty demanding,
and that is presumably a tough target to meet. Let's just
hope the fab that makes KVM chips, isn't in some third-world
country There are older fabs, that make ancient chips
(RS232 UARTs, parallel ports), where the fab would be unlikely
to be able to handle full HDMI rates.

Paul

 

[Flasherly]

I

understand that if I go with DVI or HDMI, I can convert to the other
with just a cable adapter. But, if I do go with VGA, does that pretty
much rule out watching videos online in High Definition?

-
A (S)VGA, 15-pin connector is cool, tho also heading backwards, into
the past. Yea, HDMI/DVI stuff is where it's "at" - considering those
bargain 32" and 40" monitors now, television-tuner monitors if you
prefer, are invariably fewer in number with an available VGA
connector. HDMI/DVI at a minimum below SMART-class "televisions,"
iow.

Side note - saw some real nifty cables, $15US or so, on EBAY for
converting from VGA<>HDMI/DVI;- the thing is, there needs be "active"
electronics going on (voltage potentials), so it's not just a matter
of pin-swapping around stuff from one port standard to another. Way
cool for gear freaks and propeller-twirley heads.

 

[David]

At Tue, 04 Feb 2014 00:38:18 -0500, Flasherly rearranged some electrons to
write:

understand that if I go with DVI or HDMI, I can convert to the other
with just a cable adapter. But, if I do go with VGA, does that pretty
much rule out watching videos online in High Definition?

-
A (S)VGA, 15-pin connector is cool, tho also heading backwards, into the
past. Yea, HDMI/DVI stuff is where it's "at" - considering those
bargain 32" and 40" monitors now, television-tuner monitors if you
prefer, are invariably fewer in number with an available VGA connector.
HDMI/DVI at a minimum below SMART-class "televisions," iow.

Side note - saw some real nifty cables, $15US or so, on EBAY for
converting from VGA<>HDMI/DVI;- the thing is, there needs be "active"
electronics going on (voltage potentials), so it's not just a matter of
pin-swapping around stuff from one port standard to another. Way cool
for gear freaks and propeller-twirley heads.

Some of those nifty cables assume you are using DVI-I, which includes the
analog signals. DVI-D or HDMI does not have those signals present. If
the DVI connector does not have the 4 pins on the right with the 'cross'
around them, then it is DVI-D and the nifty adapter MIGHT not work.

HDMI to VGA would require some kind of active devices.

 

[Flasherly]

Some of those nifty cables assume you are using DVI-I, which includes the
analog signals. DVI-D or HDMI does not have those signals present. If
the DVI connector does not have the 4 pins on the right with the 'cross'
around them, then it is DVI-D and the nifty adapter MIGHT not work.

HDMI to VGA would require some kind of active devices.

This one looks dated, and he isn't getting into the guts of what the
cable I described is doing, actively, with electronics...

I do have, btw, that HDMI, believe it is, to the far left of the first
picture in the article, on my newest PCI-E vidcard which I do not use.
(I'm still running 15-pin VGA connectors out from the MB's vidchipsets
to my monitors/televisions, a 32 and 40") That PCI-E videoboard does
work, however, with a standard HDMI-to-VGA connector I've tried;- the
center pictured DVI, I also have on that card, I haven't tried yet on
the one TV I have with DVI. Kinda pointless for me to go the
active-cable VGA-DVI route (rather than straight DVI-DVI).

Half lazy, actually, and I've run my 40" up to its native 1900x1020,
and it doesn't look one crap better, except for making the OS XP/SP3 a
major pain in getting some sort of readable font scheme. Though I may
not have the most pointy eyeballs around, I do sincerely doubt there's
an OS around, yet, capably engineered to take full advantage of
present high pixel resolutions. Damn shame, too, as the 40" was
relatively dirt cheap this past holiday season for last-year's model,
$250 sale.

http://www.pcworld.com/article/1966...DVI_and_HDMI_for_Your_Monitor_Connection.html

No need for HDMI unless planning to watch Blu-ray movies.

DVI also supports the HDCP protocol necessary to view that kind of
protected video content.

With a DVI cable, there's a pure digital signal (VGA is analog) and a
much sharper picture at higher resolutions.

 

[DK]

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

Those USB to PS/2 adapter don't even work reliably work for simple things.
I love my old SGI keyboards. The machine at work does not have PS/2
however. I tried 3 different adapters for it. They all work but far from perfectly.
When typing fast, it frequently goes "crazy", missing letters and/or inserting
random crap.

Pretty sad considering that I have yet to find a mechanical keyboard that would
be as nice as those old SGIs.

DK

 

[Paul]

Those USB to PS/2 adapter don't even work reliably work for simple things.
I love my old SGI keyboards. The machine at work does not have PS/2
however. I tried 3 different adapters for it. They all work but far from perfectly.
When typing fast, it frequently goes "crazy", missing letters and/or inserting
random crap.

Pretty sad considering that I have yet to find a mechanical keyboard that would
be as nice as those old SGIs.

DK

http://www.nekochan.net/wiki/Keyboards

"SGI MIPS Systems, PC Keyboards, and KVMs

While many SGI MIPS systems have the ubiquitous PS2 keyboard
and mouse interface, SGI elected to use the less common keyboard
"scan code set 3." Scan code set 2 is more commonly used in the
PC world. While most PS/2 keyboards work when directly connected
to an SGI system, some KVMs seem to translate only a fairly rigid
implementation of scan code 2, resulting in compatibility issues.

Some KVMs have the ability to transparently relay scan code set 3,
some require a jumper or configuration change to do so, and others
apparently pass everything through using the more common scan code 2.
For instance, at least one model of KVM works as long as all of the
systems connected are SGI MIPS systems; if one of the connected
systems is a PC that uses scan 2, as soon as that system is selected,
the key mapping is incorrect for the SGI systems and cannot be reset
without removing the PC and restarting the SGI systems.
"

Maybe the adapter just isn't ready to deal with that.

According to this, the 8042 in the SuperIO does some translation.
Or, at least it can be requested to do translation. I didn't know
that was what it was doing.

http://en.wikipedia.org/wiki/Scancode

Maybe the trick would be, to find out if the mode can be
switched, inside the keyboard. If the keyboard has a name
or model number, you may be able to track down what options
it might support.

On old Sun keyboards, there was a DIP switch hidden underneath,
which changed language mappings or something. A nerdy joke,
was to flip over the keyboard on an unsuspecting user, and
change the DIP switch setting. And then, watch the fun. So
maybe the keyboard has some options in it, somewhere.

Also, on this project

http://rshockley.dyndns.org/indigo.htm

http://rshockley.dyndns.org/schematic.gif

the interface on the right uses a MAX232 level shifter. (I think
that's the end for the SGI machine.) As if the SGI connector
uses RS232 levels, and not 0 to 5V PS/2 levels.
So there are some other differences as well. It's possible
to do RS232 (just barely), using unipolar implementations,
and some kludge like that was done with some Apple
computer I used in the past. Something to do with
the serial port it used.

Somewhere in all that weirdness, is your problem

Paul