Keyboards that don't play well with KVM switches or USB hubs?

[zslane]

So I discovered something illuminating about mechanical keyboards and KVM switches and USB hubs. Not all keyboards play well with them.

I didn't notice this with any of the Filco Majestouch-2 boards I'd used, or with the one WASD V2 keyboard I used for a while. Nor with my Topre RealForce or Noppoo EC108. But I've definitely noticed it with the Varmilo VA108 that I've been using at work for the last couple of weeks. Keypresses will sometimes go unregistered, or a key will often just repeat endlessly until another keypress is registered. "Lock" key LEDs will shut off even though the state of those keys is still in lock mode (NumLock being the most noticeable example).

At first I thought there was something wrong with the firmware in the board. But then I googled this phenomenon and noticed that a lot of folks encountered issues with other keyboards (not necessarily mechanicals) when connected to KVM switches or USB hubs. Here at work where I use the Varmilo VA108, I have my computer connected to a Gefen KVM switch. As soon as I unplugged the Varmilo from the KVM and plugged it directly into one of the computer's USB ports, these issues disappeared.

Is this a well-known phenomenon? I don't ever see anyone talk about it.

[iLLucionist]

Couldn't you use a software solution perhaps? Every USB device should have it's own identifier right?

http://synergy-project.org/

[TheInverseKey]

If you are using the USB hub could be that the Linux disrto cannot find the driver for the usb hub?
Also it is always better to plug the keyboard directly into the host mobo usb port.

[zslane]

Yeah, I agree that is it better to connect directly to the computer. And in my case I can do that; I don't need the KVM (I used to at one time, but not anymore).

But for people who need a KVM switch, they don't really have a choice. They can't connect directly to the mobo USB ports. Maybe it depends on which manufacturer and model of KVM switch is being used, but it is interesting (and disheartening) to learn that something about (some) KVMs (and, reportedly, some USB hubs) can interfere with the proper transmission of keypress and keystate information from a modern mechanical keyboard.

[TheInverseKey]

Yeah, I agree that is it better to connect directly to the computer. And in my case I can do that; I don't need the KVM (I used to at one time, but not anymore).

But for people who need a KVM switch, they don't really have a choice. They can't connect directly to the mobo USB ports. Maybe it depends on which manufacturer and model of KVM switch is being used, but it is interesting (and disheartening) to learn that something about (some) KVMs (and, reportedly, some USB hubs) can interfere with the proper transmission of keypress and keystate information from a modern mechanical keyboard.

Hardware will be hardware....

[itzmeluigi]

Make sure NKRO is disabled on the Varmilo VA108, some keyboards have it enabled always, a lot of KVM switches dont work well with NKRO enabled.

[zslane]

How do I disable NKRO?

[itzmeluigi]

For the Varmilo VA108 im not sure, but if it has a manual check if theres any type of FN combo, or DIP switches on the back to disable it.  Sometimes there might not be a way to disable it, it was like that with the Ducky Shine 3 and Ducky Mini where NKRO would be enabled always but they later released a firmware update to disable NKRO.

You mentioned that the KVM works fine with a Filco MJ2, WASD V2, Realforce and Nopoo EC108, and all those boards dont have NKRO enabled by default, so its most likely NKRO causing the Varmilo board to not work with the KVM.

Edit: Yup it seems Varmilo boards have NKRO enabled by default without a way to disable it
https://www.reddit.com/r/MechanicalKeyboards/comments/2mmj3j/help_varmilo_va87m_work_on_os_x/
https://geekhack.org/index.php?topic=65139.msg1640109#msg1640109

[zslane]

Thank you for all that info!

I'm just glad it works fine when I avoid the KVM (which I don't need anyway). Still, it would be nice to be able to disable the NKRO over USB since I don't really need that either.