I have a Surface Pro 7 connected to the docking station via the USB-C, the monitors connected via the Displayport work fine. When I connect a 3rd monitor to the HDMI port, the screen is not recognized. I believe Surface Pro &'s support ALT-MODE for USB-C. I have tried all the troubleshooting guides, but it still doesn’t see the monitor. Any help would be appreciated.


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

The Surface Pro 7 does support USB-C DisplayPort Alternate Mode, so we would expect the HDMI port on the dock to be able to function.

May I assume you’re using our provided USB-C to USB-C cable? (If not, some USB-C cables do lack the ability to carry the DP Alt Mode signal which would cause the HDMI to not function.) If you are using the provided cable, it’s also possible there could be a driver issue causing issues with DP Alt Mode functionality.

We have a troubleshooting tool that helps us find out what is going on in situations like this. If you’re able, please plug the dock with a monitor attached to the HDMI port into your computer, then go to this page and follow the instructions there:


When emailing us the diagnostics results please mention “Ticket 377472” in the subject line, don’t post the diagnostics here.

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

Thanks again for contacting Plugable support and best wishes!

Joshua Henry
Senior Engineer | Product Owner
Plugable Technologies

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