UD-ULTCDL: only 2 display outputs are working, and the mouse and keyboard stpped

Greetings. I purchased an UD-ULTCDL a few months ago. I recently upgraded to a 3 monitor workstation, and the 4k display output is not working – the third display, which is plugged into the 4k port, displays nothing.

Additionally, when I installed the driver at https://plugable.com/drivers/displaylink (in an attempt to get the 4k port to start sending data), the mouse and keyboard stopped working. They work when they’re plugged directly into the laptop, and when plugged into other systems. In fact, I’m writing this message with the same keyboard, plugged into another PC.


Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

Not all computers support the 4K output as it requires USB-C VESA DisplayPort Alternate Mode video output support. This can also be affected by the USB-C cable if you’re not using the cable that shipped with the dock. What make and model computer are you trying to use our dock with? Also can you verify that you’re using the cable that shipped with the dock?

For the keyboard and mouse not working, I’m unsure why this would have occurred after installing the DisplayLink drivers (these drivers are for the 2K HDMI, DVI, Ethernet, and audio, but shouldn’t affect USB operation or the 4K HDMI port). I’d recommend resetting the dock and seeing if that helps:

If you haven’t already done so, fully unplug the dock from all devices, power, and USB-C cable to the host computer. Wait about 30-60 seconds, then reconnect the power cable first, USB-C host cable next, and USB devices last. Sometimes a reset in this order can resolve this issue.

Please don’t hesitate to let us know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry

Senior Engineer
Plugable Technologies

http://plugable.com | http://performance.plugable.com/

Sorry for the late reply. I’m using an ASUS laptop, model GL703V. I’m not finding if it supports Alternate Mode. Do you know of a resource that can tell me if the motherboard supports it?

I unplugged the UD-ULTCDL this morning, and I’m about to plug it back in. I’ll use the supplied cable. Incidentally, can you tell me the cable type that shipped with the unit? I want to look into getting a longer one, as my laptop stand is further away from the dock than the cable is long.

I let the unit sit for a few hours with everything unplugged. I plugged the cables back in, in the order you specified, using the cable that shipped with the unit. The mouse and keyboard functionality were not restored.

No problem, thanks for the laptop info. I’ll see what I can find out for you and report back.

For a longer cable you’d need to make sure it is capable of USB 3.1 Gen 1 or better (Gen 2 or passive Thunderbolt 3). You should be able to use a cable up to 2 meters long without issue as long as it meets the above requirements.

Thanks for trying the reset, sorry that hasn’t helped!

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I’ve taken a look through the diagnostics and didn’t see anything worth mention, however, I went to ASUS and pulled up the full system specifications and according to ASUS your system has a data-only USB Type-C 3.0 (USB 3.1 Gen 1) port. This means it lacks the ability to output USB-C VESA DisplayPort Alternate Mode video that is required by our dock for the 4K HDMI output to function. Unfortunately this means that your system unfortunately lacks the required hardware support for our dock to operate with three displays.

We may need to offer you a return for a full refund since your system isn’t fully compatible with our dock.

I’m sorry for this bad news!

That’s ok, thanks for looking it up. I bought the unit through amazon, can you still process a return?

Thanks for the understanding. I can definitely process a return. I will reach out to you directly via email about it in just a moment.

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