I’m not sure there is a better way to word the title. What I have here is my personal laptop (Surface Laptop Studio) connected to the Plugable TBT4-UDZ, which is then connected to the Terived 2 Port HDMI KVM Switch, and then my work computer (Dell Optiplex 7040 SFF) also connected to the KVM switch. This whole deal has been a process, to say the least. I have had so many issues, but I think I have most of them figured out.
So for my work computer, it has 2 x DP out and 1 x HDMI out. What I have there is two of these cables from the DP out to the KVM switch and then of course a regular HDMI to the KVM switch. This works perfectly.
What I’ve really struggled with is with my laptop to the docking station and then to the KVM switch. I have tried several other KVM switches and have not really had any luck with them. I think I finally narrowed it down to a bad cable. Instead of using the included Thunderbolt 4 cable I was using a longer USB 4 cable. Once I switched to the Thunderbolt 4 cable it all seemed to work ok. That was when I went straight from the docking station to the monitors, since the KVM switch just came today. Well, then something still wasn’t working right. Turns out for the docking station I can’t use the DP-to-HDMI cable I have, I needed an active adapter. Thankfully I had one of those laying around. I got that hooked up and bam, it worked, I could switch between personal and work computer, and my mouse/keyboard would switch to the appropriate computer and all three monitors would display the appropriate displays.
The issue is with kind of how it is set up now. I tried to map out exactly which cables go to where. I have everything just hooked up right now with a bunch of long cables. I wanted to make sure everything worked before I put everything back in its place and used appropriate length cables to connect everything back up. But it was driving me nuts how the displays were out of order when I went to identify the monitors. I have a big monitor in the middle flanked by a smaller one on each side. I want the monitors to be like this: [2][ 1 ][3], if that makes sense. So I tried swapping out the order of the cables in the docking station and not all three monitors would display again. So then I tried changing them in the back of the KVM switch. That didn’t work either. I disconnected all three cables from both sides of the docking station and KVM switch and plugging them in one-by-one. I started with the DP-to-HDMI, plugging it in to the DP on the docking station and then to the KVM switch. The middle monitor fired up. Then I connected HDMI from the docking station to the KVM switch. The 2nd monitor fired up but then the first one went blank. I connected the 3rd cable, and that monitor fired up. The 1st one that initially fired up and then went blank stayed blank. The 2nd monitor stayed on as well. I restarted my computer a couple times, and that didn’t help. I left everything plugged in to the docking station but swapped some of them around in the back of the KVM and there would be just two monitors that were working with one blank one. The working and blank ones changed with each cable swap. I FINALLY got a combination figured out where all three monitors are working again, but I’m just trying to figure out… what is going on here? Do they need to be hooked up in a particular order? Does it matter if on the docking station I’m using 2 x HDMI out and 1 x DP out which of the DP I use? Can anyone help me make sense of this?
Thank you for contacting Plugable support! I’d be more than happy to assist you. My apologies for the issues that you have been experiencing.
To be fully up front, based on our experience you may find that some KVMs may work better than others, but generally we’ve seen where most KVMs can be problematic when used with docking stations. Due to the historical problems we’ve seen with KVMs and docking stations overall we do not recommend the use of KVMs with our docking stations if possible as display results often may be unstable or sometimes not even work at all. Many of the issues you’ve experienced are issues that we can see with KVMs when used with docking stations (displays blanking out, not being detected consistently, display arrangement issues, etc). If the dock and displays are working correctly without the KVM, then I suspect the KVM is causing your issues.
You mentioned: “I want the monitors to be like this: [2][ 1 ][3], if that makes sense. So I tried swapping out the order of the cables in the docking station and not all three monitors would display again. So then I tried changing them in the back of the KVM switch. That didn’t work either. I disconnected all three cables from both sides of the docking station and KVM switch and plugging them in one-by-one.”
Changing physical connections for the displays or what order the displays are connected in generally does not determine the display arrangement. Typically Windows records a record of the display information giving each display a unique identifier in software, so even if moving to a different port or connecting in a different order Windows should remember how everything is supposed to be arranged. So it should not matter in which order you connect cables between the dock and KVM, or between the KVM and monitors.
If your monitors are working out of order then you need to correct the display arrangement in the display settings in Windows. So instead of physically trying to change cables or move displays around physically you will just rearrange your displays virtually in the display settings control panel. If this still isn’t working we have seen due to how some KVMs operate where the dock may incorrectly identify monitors connected through the KVM. Sometimes KVMs change how the monitors are identified in software and it can cause issues for the aforementioned record/unique identifiers Windows keeps for the attached displays which can result in seemingly random monitor arrangement. Sadly issues like this with KVMs in use are often not something that can easily be resolved without lots of trial and error.
Please don’t hesitate to let us know of other questions.
Thanks again for contacting Plugable support and best wishes!
Do you have any ideas that can help me in this situation? I have your docking station that my personal laptop is connected to, with my three monitors. Is there a way somehow I can connect the work desktop computer to the docking station as well?
You’re most welcome. Unfortunately I don’t know that we have a perfect solution here. Your desktop system for work is incompatible with this docking station, it lacks both USB-C and Thunderbolt looking at the specifications so that wouldn’t be an option. We make other docks that could work with both systems and help avoid the use of a KVM, and also be switched between them with an additional product (USB 3.0 switch box), but there would be compromises.
The docks that would work in this way through a USB 3.0 switch would only offer two displays (although a third could be added with an additional USB graphics adapter) and the dock won’t be able to offer charging to your computer so you would have to connect the stock charger for it. In addition these docks would require DisplayLink USB graphics driver software to be installed, which may not be supported by your work system if you do not have admin access.
If you believe that the above setup could possibly work for you given the limitations I’ve mentioned I could make more specific recommendations for what combination of products to use.
