The UHK exposes a sophisticated USB interface that many KVM switches can't deal with. If a KVM switch doesn't work with the UHK, it doesn't mean that it won't ever work with the UHK. It may only be a matter of updating the firmware of the switch.

Please note that firmware versions before version 9.0.0 implemented 6-key rollover (6KRO), which only allowed the UHK to report at most 6 pressed keys + modifiers at once. Starting from version 9.0.0, the firmware implemented N-key rollover (NKRO), allowing the host to read all pressed keys. Unfortunately, as it turned out, NKRO made KVM switch compatibility worse, as KVM switches usually don't support it. We'll make the UHK firmware automatically fall back to 6KRO, according to this GitHub issue.

(*) It's important to note that there are passive and active KVM switches. Passive switches simply let USB traffic through and rely on external buttons for switching. Active switches, however, parse USB traffic to capture certain key combinations to trigger switching. Unfortunately, the USB parsers of many KVM switches are rather limited and only work with simple keyboards that expose a single USB keyboard interface, unlike the UHK, which exposes additional USB interfaces. This makes the UHK not fully work with such switches. The workaround is to plug the UHK into a generic port of such switches, not into a keyboard port that gets parsed. The drawback is that the KVM switch cannot capture key combinations, so switching is only possible with external buttons this way.

If your KVM switch is not on the list, please update its firmware, then submit it to us, and we'll include it.