UD-3900PDZ cable or adapter

I recently purchased a MacBook Pro (Big Sur). I’m having issues detecting my 2nd monitor which is connected to the the docking station in HDMI2 using a Displayport to HDMI cable. I am also using a thunderbolt cable to connect the docking station to the Macbook.

Do I require an active adapter to connect to Plugable for the 2nd monitor to be detected?


Thank you for contacting us, I am sorry, most DisplayPort to HDMI cables are one-way adapters from a DisplayPort Dual-Mode (DP++) output on a computer or docking station to a HDMI display and will not work in reverse ( from a HDMI output on the docking station to a DisplayPort input on a monitor ).

Does the display have a HDMI or DVI input? If so I recommend connecting from the docking station’s HDMI output to the display’s HDMI input with a standard HDMI to HDMI cable, for DVI inputs a HDMI to DVI cable can be used to connect from the docking station’s HDMI output to the display’s DVI input. DVI and HDMI share the same signal for displays up to 1080P (1920x1200 resolution specifically) and a simple adapter cable can be used to convert the HDMI to DVI connectors.

Please let me know the manufacturer name and model of the display that is not working and I will be happy to look up the specifications and make a more specific recommendation for connecting this to our docking station.

Thank you, I look forward to your reply email and we can go from here.

Plugable Technology


We’re closing this thread due to inactivity, but if you have any further questions please feel free to contact support@plugable.com and we’ll be happy to help.


Plugable Technologies