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Keyboard splitter

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dukeofthomas

Technical User
Jan 16, 2005
6
GB
Hi guys (and gals!) - I keep my computer in a separate room from my bedroom, and use extension PS2, USB and monitor leads, to route the signals into my bedroom through a small hole in the wall (as I want a silent room to work in). I have now routed a second set of leads downstairs to a spare monitor, keyboard and mouse that I had, but I've had great difficulty getting my second keyboard to work.
Initially I used what I believed to be a keyboard splitter cable, I had two, one for the mice, and one for the keyboards, but I couldn't get them to work, and then I discovered that these splitter cables only work with laptops and are intended to split one PS2 port into both a mouse and a keyboard port, whereas I want to split one PS2 port into TWO keyboard ports, and the other PS2 port into two mice ports.
I then got a USB to PS2 keyboard and mouse cable, which works to some extent, but I have an AT keyboard downstairs that I don't want to stop using (they don't make tactile keyboards any more, so I have to use it or risk RSI), and this gives me no end of problems, presumably because I am using a 5 Pin DIN to PS2 adaptor, to plug it into the USB to PS2 keyboard cable. The keyboard is almost useless - when I initially turn on the PC, the only way to get the keyboard to work is to unplug it and plug it back in to the USB to PS2 cable; then the keyboard is unresponsive, misses 50% of the keys I type, and often goes into auto repeat mode for no reason, and I get a line of the same character.
I've seen that you can buy PS2 keyboard splitter boxes, so I could use one of these with a PS2 extension cable, but they are about £35. Can I just get the necessary PS2 leads (which I have loads of) and splice the two together? Or failing that, splice them together but make a switch so I can turn one keyboard on and one off, so they aren't on at the same time (only if them both being on at the same time is going to be a problem!).
 
Keyboard ports are not meant to handle long lengths of cable, and certainly are not meant to deal with two keyboards on the same port. Same goes for the mouse, and video for that matter.

You need the KVM (Keyboard/Video/Mouse) switch for all of this to work. The least expensive models are generally passive, which I would not consider if the length of cable you need is over 12' or so. An 'active' KVM will amplify the signals and allow for clean operation over a much longer distance.

Also, most models are designed to connect one keyboard/video/mouse to two or more computers so several servers can be controlled from one station. You will need a model that fits your situation.

I would not under any circumstances begin cutting and pasting cables. It will not work reliably and my damage the keyboard controller in your computer.
 
You could possibly use a switch and swap the data lines on the keyboard cables but from the experiences I've had I believe you will be very dissatisfied, with things hanging up regularly.
The power and ground lines would need to be connected full time.
To test this you could get one of the switch only KBMs and use it to switch the cables, always switching to remote when leaving the computer.

Ed Fair
Give the wrong symptoms, get the wrong solutions.
 
Thanks for your replies guys. I'm mainly concerned about using my old AT keyboard with my USB to PS/2 adaptor, as I don't want to have to use a new PS/2 keyboard, because I've not been able to find one that has a tactile response (I'm a touch typist and need a tactile keyboard). I think I'll have to buy a Y-Key Key device, but they cost about £30 and I was hoping to avoid spending any more money.


According to this article USB keyboards are limited to 6 simultaneous keypresses - I've noticed that my keyboard acts up most when I'm typing quickly, but surely I don't press 6 keys at once when typing?

I've searched high and low for a KVM switch that allows two keyboards, mice and monitors to connect to one PC, but I can't find any, they all do the opposite: connect one keyboard, mouse and monitor to two PCs.

If I buy the Y Key Keys device, that should solve all of my problems, I can still use the downstairs mouse on the USB port (I have 5 USB cables routed downstairs, so there are plenty spare if I need them) and use the Y Keys for the keyboard. I've just purchased a VGA splitter and amplifier device for £26.44, which works at up to 50m, so that's the monitor taken care of too!
 
I've found what the problem with the keyboard is - I type too fast! If I type a little slower, and don't touch two keys at the same time, it works fine with the USB connection, but if I start typing at my usual speed, (60wpm) then the caps lock and scroll lock lights flash once and the keyboard either locks up, or goes into auto repeat mode. I've tried two other AT keyboards and they all do the same thing. I think it's when I press certain combinations of letters simultaneously.
 
Shouldn't be a problem with the keyboard. Keyboard scan will find them one at a time since that is the way the scanner works. Sounds like the conversion is falling behind.

Ed Fair
Give the wrong symptoms, get the wrong solutions.
 
Is this normal when using an AT keyboard with a USB port? I'm finding it really hard to type slowly enough for the keyboard, it locks up if I start typing too fast, and I have to unplug the PS2 connector and plug it back in (into the PS2 to USB adaptor I have).
 
I think you should go back and look at your PC and see what you can do to make it quiet and move it back into your room. Your problem is, without a doubt in my mind, distance - as stated above, the keyboard ports (and mouse and video too) are not designed with long cable lengths in mind - including multiple adapters and connectors, adding more resistance, along the way.

You can certainly do many things to cool down your system quietly - including replacing the power supply with a quiet Antec or Zalman model, replacing the CPU heatsink fan with a quiet model from Zalman or Thermaltake. Several manufactures make quiet case fans - I like Vantec and Panaflo models - if you can put in larger fans (say 120mm) in your case, they move massive amounts of air but at a much lower (and therefore quieter) RPM.

I think you can do all of the above for the same price or even less than the active (powered) KVM type device, with quality connectors and wires, that you will need.

Finally, I suggest you check out the Antec Sonata case - it is designed with sound deadening in mind. You can get it with a quiet Antec PS, it comes with one 120mm fan and can take another in front behind the "air filter" (which works great, BTW) and, with a good HSF, is really quiet. I used the Sonata for the wife's new system and with my head next to the Sonata, I hear the fans in MY machine across the room!

Note, for home theater applications, they make sound deadening padding to add to most cases that work well too.

Bill of BrightWorks Systems
AFE7Ret
9-11-2001
Never Forget!
 
The problem isn't caused by distance, I've tried it with an AT keyboard going through an AT to PS/2 adaptor, and into a PS/2 to USB adaptor, with no extension lead, and the same problem occurs. A PS/2 keyboard works absolutely fine with the PS/2 to USB adaptor on the same lead. I've tried it with 15m of lead just for fun, and it still works okay. I'm sure it's something to do with AT keyboards not liking the PS/2 to USB adaptor.
I can't just move the PC back to my room, because I use it in both the bedroom and downstairs in the living room, and I would have to buy another PC!
I've solved the whole problem by buying a 'Reverse KVM' switch, from Belkin, that takes in two keyboard and mice inputs, and gives out two monitor outputs, and polls the keyboard automatically, so it knows which monitor to display on. I can't understand why there seem to be so many KVM switches available, and cheaply, but very few 'reverse' KVM switches - I would have thought that there would be more people who have one computer but want to access it in two different places, than there are people who have two computers, but want to access them both from the same keyboard and monitor.
I'd still like to find out if anybody has ever got an AT keyboard working okay with a PS/2 to USB adaptor though.
 
I was thinking about using two wireless keyboards and two wireless mice, but they won't transmit far enough, only about 1 - 1.5m. If there was some way of beefing up the signal, that still wouldn't solve my problem, as I want to use my old AT keyboards, I have about ten of them (Viglen make, mechanical, individually microswitched keys) and don't want to have to shell out £45 each for new Cherry microswitched keyboards (I can't find any other company that makes a decent keyboard nowadays). The reverse KVM switch only cost me £20 second hand, so it was the cheapest solution.
 
people who have two computers"

People yes, but KVM switches (and many other other add-ons), are designed for the professional office.
 
miker377 said:
People yes, but KVM switches (and many other other add-ons), are designed for the professional office.

Not really - KVM switches have been around for years (like 20!) we used them server farms and the like. I've had a couple 4 in 1s for years too that I use in my shop. I have another on my SETI farm of 4 old PCs.

They work great and save costs and on extra peripherals - not to mention lugging monitors around gets old.

Bill of BrightWorks Systems
AFE7Ret
9-11-2001
Never Forget!
 
billbright:

"we used them server farms and the like"

That's what I meant, they were originaly designed for "high end" use.
 
Okay - I thought you might be referring to the once popular AB switches used often in "offices", mostly for printers - 2 or more PCs for a printer (before sharing and networked printers) or more likely where a single PC was hooked up to 2 printers - a B&W Laser and an Ink Jet color, for example - or a fancy laser for final and a dot matrix for drafts.



Bill of BrightWorks Systems
AFE7Ret
9-11-2001
Never Forget!
 
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