2 -> 1 PS/2 Adapter Problems

[LSchaeffer]

Hello,

Some basic questions I should probably know the answers to, but I have tried to search around and have had little success. Hopefully you guys can give me some help.

First, let me describe the situation (I apologize for the length, but am attempting to be as detailed as possible):

Ultimately, I am attempting to set up a KVM switch between my laptop, and my desktop, so that I can use the same mouse/keyboard/monitor for the two of them when my laptop is docked at home.

I received my KVM switch in the mail a few days ago, and started setting things up, when I realized my laptop (A Thinkpad X40) only had 1 PS/2 input. So, I realized I was going to need some way to convert my inputs into 1 PS/2 (or a USB, but I chose PS/2, who knows why).

Out of curiousity, I decided to experiment with the KVM switch on only the desktop, to make sure everything worked properly. So I hooked up my mouse (A logitech mx 700 with a PS/2 converter) and my keyboard (A memorex who knows what, was a cheap purchase when I spilled a soda in my last keyboard), and everything worked fine. Just to make sure the other side of the cables worked, I switched which half of the setup was going to my desktop, and the other side worked fine. I even got curious enough to try plugging in the mouse and keyboard (one at a time) into the laptop, and testing that. All is well.

I wandered over to my local Fry's, and picked up a PS/2 y converter, which states "PS/2 Mouse/keyboard "y" splitter" on the packaging. So far so good. This is where the trouble begins.

First I hook everything up through the KVM switch, and when I switch to the laptop, things are weird. If I touch the mouse first, the mouse works fine, but as soon as I would touch something on the keyboard, the laptop would get grumpy, and neither imput would work properly. If I touched the keyboard first (after a reboot) then the keyboard would work fine, and regardless of what I did to the mouse aftewards, nothing would happen with the mouse.

At this point, I am not sure if it is either the laptop that has the problem (perhaps it needs a "special" converter. This wouldn't make much sense to me though. i looked through the IBM support documentation and couldn't find anything).

I have further tested both the laptop and the converter as follows:

I have tested the Logitech mouse, and another ps/2 mouse (no conversion from USB on the second mouse) directly to both my desktop and the laptop, and all function fine with direct connections.

I have also tested the keyboard directly to the laptop (through the same ps/2 port) and it works just fine that way as well.

I also am not sure exactly how the conversion process should work, but just to be extensive in my testing, I put the converter on the desktop:

plugged the adapter into the mouse slot. Plugged in both mice (different times) into both slots, regardless of the slot used, the mouse works fine. When I plug them in at the same time, niether work. Did the same test on the keyboard with identical results (although I only have 1 keybaord to test)

So ultimately, is the problem my computer, the user, the converter, or some mysterious 4th option I haven't thought of.

Any advice would be GREATLY appreciated.

 

[Fardringle]

I wish I could give you a positive answer, but in the mutiple times I have tried to do something similar to what you are doing on desktop and laptop PCs, I have only once ever got it to work. That one time was on a desktop PC. I have never had a PS/2 splitter work on any laptop of any brand (I've tried Gateway, Compaq, Dell, and IBM)...

 

[LSchaeffer]

I could definetely see the laptop being the issue. However, I am hoping the issue is just the cable itself. I have since called IBM technical support, and did my best to get the tech support guy to track down all their documentation of "their splitter", but it doesn't seem he had any available (that he would give me at aleast). my goal was to see if maybe the pin setup on the iBM laptop was different than normal, and that I would have to buy the IBM splitter. (THe IBM splitters costs a whopping $35, would rather deal with a second mouse).

Anyway, I think I am just going back to Fry's, and I am going to get a usb to ps/2 adapter for one of the ps/2 ports (probably the mouse). This way, one ps/2 connector goes from the KVM switch to the ps/2 port in the laptop, the other ps/2 connector converts to a usb, and goes into a usb slot on the laptop. I think that should work. Any reason it wouldn't?

 

[Fardringle]

That's certainly an easier (and much cheaper) option than talking to IBM, and I don't see any reason why it would work. I do the same on some a few of my systems that don't have two PS2 ports and it hasn't failed me yet. I use them on the mouse on the few that I do this with. I haven't actually tried with the keyboard so I can't say whether or not it would work there...

It's possible that your particular KVM switch won't like the USB adapter, but it can't hurt to try and it shouldn't cost more than a dollar or two to get a simple PS/2 to USB adapter. And if Frys doesn't have one, I have a handful of them somewhere at home and would be happy to send you one for the cost of postage.

 

[ZYFER]

To be honest, I think you should have went with the USB option lot that helps you now right? Laptop PS/2 ports are designed for operation of single device, I do not believe I have ever seen a working case with an adapter like that.

 

[LSchaeffer]

Not that I don't believe you (Especially since I am seeing the issue I am now), but the only reason I disagree is that the thinkpad specifically advertised the fact that you can use a splitter in order to use both devices. Frustrating that it is not the case. I am returnign to fry's today to return my splitter cable, and buy a usb to ps/2 adapter, and that will be the end of that