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nebb-tgr
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Wierd keyboard behaviour - Sometimes only windows key works

Hello,

We have a quite wierd problem on one of our projects. We have three PC's all connected with 1m cable to a KVM-switch with USB. The KVM switch is connected through a 10 meter amplified cable to a USB-hub. The USB-hub is in turn connected to a mouse and a wireless keyboard.

We are experiencing two separate problems, but both seem to be related to the communication between the USB-units and the PC.

Before I explain the problems, I need to point out that 95% of the time, everything works fine. The doesn't seem to be any kind of event that occurs before the problem appears, it just happens.

Problem 1 - Keyboard:
Writing normal text doesn't work anymore. But the windows key works.
Example: You can press the windows key to make the start-menu appear, but you can't write anything in the "Search programs and files" text box. I haven't checked all keys, there might be more working keys than the windows key.

Problem 2 - Mouse:
This seems to be a general problem that is always there. When you click a button, the mouseclick is not registered before you move the mouse. We use industrial rollerballs, so it is not natural to move the rollerball when you click.

I thought that all communication from mouse and keyboard was interrupt-driven. That should meen that a mouse-click would be transferred instantly. And I didn't think there would be any priority or anything on the kind of keys that are transferred. Why would the windows key work while the others dont?
HardwareMicrosoft Legacy OS

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nebb-tgr

8/22/2022 - Mon
SOLUTION
Callandor

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nebb-tgr

ASKER
We have tried powering the USB-hub. That didn't help. I don't think general USB-hubs shape up the signals. We could try another USB-hub though.
SOLUTION
Callandor

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nebb-tgr

ASKER
- Change the keyboard
 - Change the hub
 - Try 2x 5m amplified instead of 10m amplified.

I will let you know how it goes.
nebb-tgr

ASKER
Further explanation:
There are two operator chairs with the identical setup. This means that this is not a freak component failure or similar. It is semi-reproducable, i.e. it will happen sometime between 1 hour and 2 weeks.

Because changing the cable is such a hassle, we have decided to try to change out the keyboard and USB-hub in the hope that this will fix the issue.

As before, I will let you know how it goes.
Your help has saved me hundreds of hours of internet surfing.
fblack61
nebb-tgr

ASKER
Thanks for the feedback. Never did get around to testing this further. So I'm awarding points based on activity. :)