"Plugable 12-in-1 USB C Docking Station Triple Monitor" only detects 2 monitors

Hello. I have 3 of the same monitors connected to the dock, but it only detects two plus the laptop screen. I’ve installed the most up to date drivers and it didn’t help. I then uninstalled, cleaned and reinstalled, but it still does not detect the third monitor.

What are some things I can try?


Thank you for contacting us, I am sorry this is not working as expected and I am happy to help!

The UD-6950PDZ USB-C Triple Display Docking Station relies on two graphics technologies to support up to three external displays:

  1. USB-C DisplayPort Alternate Mode, an optional USB-C port feature which connects the computer’s graphics controller to the USB-C port is used to control the docking station’s “Display 1” output port-pair. This also requires connecting the docking station directly to the host computer’s compatible USB-C port using the original USB-C cable provided with the docking station.
  2. DisplayLink USB Graphics Technology, the DisplayLink software emulates graphics hardware to extend the computer’s display capability beyond the manufacturer’s design. This is used for the docking station’s “Display 2” and “Display 3” output ports.

For the non-functional display, please let me know which port it is connected to on the back of the docking station, each port is labeled just below the HDMI output.

Additionally, please let me know if the docking station is connected directly to the host computer using the original USB-C cable provided with the docking station, or if it is connected with another USB-C cable, or through another device or adapter.

Thank you for these additional details, I look forward to your reply email and we can proceed from here.

Plugable Technology

Hello. Thank you for your reply.

The monitor that is not being detected is in HDMI1 (Or displayport 1 as I tried both). I am using the USB-C cord from the docking station to my laptop.


Thank you for replying back and confirming the non-functional display is connected to the “Display 1” output and the docking station is connected directly to the host computer with the original USB-C cable provided with the docking station.

Our next step is to check to ensure the host computer supports USB-C DisplayPort Alternate Mode.

For Windows:

  1. Open the Start Menu and search for “msinfo32” and launch the first search result
  2. Please let me know the values from the following entries ( on the right column ):
    “System Model”
    “System SKU”
  3. Please feel free to attach a screenshot of this window to your reply email if you prefer by using the Windows Snipping Tool ( from the Start Menu search for “Snipping” ) and I can get the details from there

For macOS:

  1. Open the Apple Menu > About this mac…
  2. Please let know the system model details and macOS version from this page
  3. Please feel free to attach a screenshot of this window to your reply email if you prefer by using the macOS screenshot hotkey combination [Command ⌘]+[Shift ⇧]+[4] then dragging a selection box around the window, the screenshot will be saved to the desktop and can then be attached to your reply email.

I will check the system manufacturer’s specifications to ensure this computer is fully compatible with this docking station.

Thank you,

Plugable Technology

|System Manufacturer|Acer|
|System Model|Aspire A515-54|
|System Type|x64-based PC|
|System SKU|0000000000000000|


Thank you for the additional details, I am sorry, based on Acer’s product specifications page and user manual this computer does not appear to support USB-C DisplayPort Alternate Mode and is not fully compatible with this docking station.

From the system specification page:

Acer only claims the port supports “USB 3.1 Gen 1 (up to 5 Gbps)” with no mention of either USB-C DisplayPort Alternate Mode, or USB-C Power Delivery. This most often means these two optional modes are not supported.

Similarly from the user manual ( https://global-download.acer.com/GDFiles/Document/User%20Manual/User%20Manual_Acer_1.0_A_A.pdf?acerid=637255515614904290&Step1=NOTEBOOK&Step2=ASPIRE&Step3=ASPIRE%20A515-54&OS=ALL&LC=en&BC=ACER&SC=PA_6 ) page 11:

Acer does not specify that this port supports USB-C DisplayPort Alternate Mode or USB-C Power Delivery, again normally indicating this computer does not support these features.

And this note on page 61:

In this case Acer is incorrectly describing USB-C DisplayPort Alternate Mode video capability as “Thunderbolt video”, a common occurrence in Acer’s user manual and product documentation, the two technologies are similar but it would be more correct to use “DisplayPort Alternate Mode” when discussing a non-Thunderbolt 3 port and its features.

I am sorry, based on the system specifications and user manual this computer is not fully compatible with the Plugable UD-6950PDZ docking station, or our other USB-C Triple Display Docking Stations, and will require either connecting the third display directly to the HDMI output on the computer, or adding a separate USB 3.0 to HDMI or USB 3.0 to DisplayPort adapter to the docking station.

If this docking station is only being used with this computer and within 30 days of purchase, I can help to return the docking station for a full refund and make a recommendation for a docking station and graphics adapter that are both fully compatible with this computer for supporting three external displays. To start the return process please send an email to ‘support@plugable.com’ with the subject line ‘Ticket #386782 - Attention Pat’ and in the body of the email please include the following details to start the return process:

  1. The Amazon Order ID ( available from amazon.com/orders ) for the original purchase of the UD-6950PDZ ( in the form of “###-######-#######” )

  2. The serial number from the bottom of the docking station ( in the form “####A#####” )

  3. Your full, preferred shipping address (in the form below) for receiving the replacement UD-6950PDZ, for addresses outside of the United States please include a phone number we can provide the shipper in case they need to contact you to arrange delivery.

    Company (if shared)
    Street Address
    Suite or Unit Number
    City State Zip

Please let me know how you would like to proceed and we can go from here.

Plugable Technology

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