Dell Dock UD22 cannot detect second monitor
 

Hello,

I have a M1 Macbook Air. I'm trying to connect to a Thunderbolt display via thunderbolt 2->thunderbold 3 adapter https://www.apple.com/shop/product/M...bolt-2-adapter

With the second USB C slot, I've plugged in the Dell UD22 but DisplayLink says it's unable to detect second monitor. The Samsung monitor is connected to the UD22 via HDMI.

When I unplug the Thunderbolt display, the UD22 is able to display onto the monitor.

Previously, I used Pluggable and was able to work without an issue. https://www.amazon.com/dp/B0BKLT853Z...roduct_details

In brief, I believe there are several factors contributing to the behavior. However, in order to keep things simple I will ask two quick questions:

1. Can you connect the Samsung monitor to the DisplayPort video output port on the back of the UD22 dock, specifically the one that is closest to the dock's Ethernet RJ-45 port?

2. The Plugable product you mentioned is based on DisplayLink technology. Do you still have the DisplayLink Manager Application installed on your Mac?

1. Yes, I've tried all 3 ports, HDMI and both displayports. I am plugged into "displayport in" on my samsung monitor, there is also a "displayport out"

2. Yes, still installed version 1.10.2 (building 14)

Important note, do not use the 'DisplayPort Out' port within your display. It won't work in this case.

The manual for your UD22 dock --> https://dl.dell.com/content/manual84...language=en-us indicates that the DisplayPort output closest to the dock's Ethernet port is driven by the DisplayLink chip inside of the dock.

This means that as long as the DisplayLink Manager Application is installed and correctly configured on your Mac this port should work.

Let's simplify the setup for a moment.

Please disconnect the Thunderbolt display from your Mac. Please connect the Samsung display to the UD22 DisplayPort output that is closest to the Ethernet port.

Does the Samsung display work in that simplified configuration?

Okay, got it all to work.

For anyone reading along:
0. install displaylink software.
1. Make sure to use a displayport to displayport cable. displayport to usbc did NOT work
2. plug display port monitor into displayport (closest to ethernet in on UD22).
3. Plug the UD22 into macbook air
4. plug in thunderbolt monitor (via usbc) to macbook air.

Thanks for your help @rboerner

Glad you got everything working, and you are welcome for the assistance.