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mario-on-mac

macrumors newbie
Original poster
Nov 3, 2022
3
1
I have two of the LG UltraFine 4k monitors, and I'd like to use some sort of switch or KVM to allow either of my two computers (work and personal) to use the monitors (I want to use both for my work computer during the day, and both on my personal computer at night). However, it seems that if I use a DVI to USB-C cable, that the monitors aren't recognized at all. All of the KVMs that I'm finding have DVI or HDMI output, so that leaves me wondering if I can even use these monitors with a KVM. Does anybody have experience using these monitors with any sort of KVM? They work great when connected directly to the computers with a USB-C cable.
 

joevt

Contributor
Jun 21, 2012
6,769
4,103
Which LG UltraFine 4K displays do you have? The older one (21.5 inch 4096x2304) requires Thunderbolt. The newer one (23.7 inch 3840x2160) can use Thunderbolt or USB-C/DisplayPort.

If you use USB-C/DisplayPort then the USB ports will be limited to USB 2.0 speed.

You could use a DisplayPort 1.2 KVM. You'll want to use a cable that takes DisplayPort + USB 2.0 as input and outputs USB-C so that you can use all the USB features of the displays.
https://forums.macrumors.com/threads/alternative-to-the-belkin-vr-cable.2378619/
https://www.store.level1techs.com/products/p/dp-repeater-hdmi-splitter-6sha9-yznx5-zm58w

There may exist USB-C KVMs. Not sure if there are any that support dual display.
https://www.store.level1techs.com/products/hardware

Another alternative is a simple USB-C switch but you would need one for each display. There's some threads in Mac Rumors discussing these, like this one:
https://forums.macrumors.com/threads/two-computers-and-one-studio-display.2337419/page-20

Which PC do you have? There does exist a Sabrent Thunderbolt 4 KVM which requires at least a Thunderbolt 3 Mac. I'm not sure how well Thunderbolt 4 works with Thunderbolt 3 PCs. With a single Thunderbolt 3 connection, you can support two 4K displays but some PCs don't support dual display from Thunderbolt 3. The M1 Mac doesn't support dual display from Thunderbolt.
 
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mario-on-mac

macrumors newbie
Original poster
Nov 3, 2022
3
1
Thanks for the suggestions. Both my PC (a Dell Latitude 5420) and my Mac (a 2019 Mac Pro) have Thunderbolt 4. I have the newer UltraFine displays. I bought the Sabrant Thunderbolt 4 KVM and it works. For some reason, I couldn't get USB-C to DisplayPort cables to work with these displays, but maybe I was using the wrong cables.

With my current configuration switching away from the PC and back again does cause the windows to lose their position, but the Mac retains them. But, honestly, it isn't a huge deal. The displays are great, so that's a small price to pay.
 
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