KDC203-P24 No display on HDMI 1

Michael Hermann

April 25, 2026 18:25

Hello,

First time setting this up and I plugged in the included cable to my PC2 HDMI port on the device and the other end on my EVGA GEFORCE RTX 3090 HDMI port. I then pluged the display 1 HDMI into the device and the other end into HDMI 1 of my OLED48C1PUB.

I do not get a signal. 

I tried directly plugging in my PC2 to the OLED and that worked without issue. 

Not sure what the issue is.

Thanks

Mike

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  TESmart.01

  May 07, 2026 07:26

  Hello Mike,

  Thanks for the detailed description — this helps narrow things down quite a bit.

  Based on your setup, there are two key areas to check:

  1) Input ↔ Output mapping (very important on this model)
  On the HDC203-P24, each PC2 input is directly mapped to a specific output:

  • Input A → Output A
  • Input B → Output B
  • Input C → Output C

  So if your RTX 3090 is connected to the HDMI port (Input A), the display must be connected to Output A to receive that signal.

  If multiple monitors are connected to the KVM, then the GPU also needs to feed all corresponding inputs (A/B/C). Otherwise, some outputs will not have an active signal source.

  Could you confirm whether your OLED48C1PUB is currently connected to Output A?

   

  2) Resolution / refresh rate negotiation (possible compatibility factor)
  The OLED48C1PUB supports up to 4K@120Hz, while the HDC203-P24 is limited to 4K@60Hz.

  In some cases, the GPU may initially attempt a higher bandwidth mode (e.g., 4K120), which the KVM cannot pass through. This can result in no signal during the handshake phase.

  If the cabling is already correct, please  set the GPU output to 4K@60Hz，Then check if the display comes up.

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