Hello. I am trying to use the HID Remapper (Feather RP2040 with USB Host) connected to an Avocent (Vertiv) SV340 series KVM. I have successfully flashed the RP2040 and it works great when connected directly to my PC. When I connect it to the dedicated keyboard port on the KVM, the keyboard it not recognized. The green power LED is lit and the red LED lights up when a key is pressed, however no keyboard command is processed by the KVM. It’s connected using a simple standard Dell USB keyboard. Is there a way to make it work with the KVM? Is it a USB 2.0 versus USB 1.1 speed issue? HID Remapper firmware issue? Looking for some solutions please. Thank you.
I don’t know, when we have issues it’s typically with some devices not working when plugged into HID Remapper, not HID Remapper not working when plugged into things. We had some issues with KVM switches specifically when switching, but that should be better now. Looks like it’s an expensive device, have you tried contacting the manufacturer’s support?
Thank you for the reply.
The SV340D (SV340 series in general) has reached it’s end of life and they are no longer supporting it or updating it.
Out of curiosity, it tried connecting the HID Remapper with the mouse. Same thing. Red LED senses activity from the mouse, but no mouse is detected by the KVM. Plug it directly into the computer, and it works.
Seems like really strange behavior. Would a USB 1.1 hub maybe fix it? Who knows. Clock/timing issue? What else would the KVM be looking for in regards to a USB HID signal from a keyboard?
The reason I wanted to use the HID Remapper was to remap the Left CTRL key. The KVM uses the Left CTRL key as a hot key for switching computers. In my CAD program, I use the CTRL key a lot and if I press it twice and press 2, 3, or 4 (when I manually enter dimensions), it switches to that computer. When I go back to PC 1, I have to resize all my windows and open programs. A real pain. Avocent says no way to disable the hot keys. Ugh. If I could map the Left CTRL key to Right CTRL key, it would never happen. Seemed like the Remapper was the way to go and had high hopes.
Any thoughts or suggestions would be appreciated.
Thank you.
Hello,
to my experience, this is most likely rather a speed issue than a keyboard compatibility problem on the KVM switch side. I guess the switch only accepts a keyboard on its USB console keyboard port with a quite simple USB device descriptor, only containing a keyboard and maybe an additional universal HID endpoint for multimedia keys. I have seen this on Extron USB switches with HID emulation capabilities, which only worked with plain and simple keyboards and mice. Some more tolerant models like ones from ATEN also accept a device descriptor which also contains a mouse as used in keyboard/mouse combos. I don’t know how tolerant the Avocent model is.
I guess the HID remapper would need a function to strip down itself’s device descriptor to one like a simple keyboard. Unfortunately, the remapper needs an additional webHID endpoint in its descriptor for the configuration GUI to work. It is possible to alternate between more than one device descriptor at runtime with the TinyUSB library used, but it would need additional work on the implementation. My ideas to switch between descriptors would be either a special (configurable) key combination or a hardware switch.
Best regards