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edanuff

macrumors 6502
Original poster
Oct 30, 2008
355
94
Looking at the LG 24MD4KL-B display. It appears to support either TB3 or USB-C (DP) inputs. The LG page shows both a Mac and an iPad Pro simultaneously connected to it. How does it switch between them? I'd like to hook up a 2013 Mac Pro using the TB2 to TB3 adapter and a PC using the Moshi bidirectional USB-C DP cable but there is no information on how it decides which to use as the active input. Has anyone tried using two inputs to the 24MD4KL-B and knows what happens?
 

carlover670

macrumors newbie
Apr 1, 2020
19
9
One of the two thunderbolt 3 ports are how you connect the monitor to a computer. Unfortunately you can only have one computer connected at a time. The three usb c ports are for accessories, consider it a usb hub.
 
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joevt

macrumors 68040
Jun 21, 2012
3,074
1,394
If you don't want to switch cables when you switch computers connected to the display, then you need a KVM switch. There exists a Thunderbolt 2 KVM switch, but the PC doesn't have Thunderbolt, so you'll want to use a DisplayPort KVM switch. The Moshi bidirectional USB-C to DP cable should work wth the new 24 inch LG UltraFine 4K display but if you want to use all the features of the display (brightness control, audio, USB ports), then you'll want a method that includes USB 2.0 (like Wacom Link Plus or VR 2 cable). The old 22 inch LG UltraFine 4K requires USB (or maybe the Alogic cable). With USB, your KVM switch should also include USB.

For the PC, it may be possible to install the Boot Camp driver that allows brightness control of the LG display using the Boot Camp control panel (I haven't checked that - it works for the Apple Pro Display XDR).
 
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edanuff

macrumors 6502
Original poster
Oct 30, 2008
355
94
Thanks, good information. I’ll try it with a bidirectional DisplayPort to USB-C cable and the IOGear 2-Port Cinema 4K KVM and report back if it works.
 
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edanuff

macrumors 6502
Original poster
Oct 30, 2008
355
94
FWIW, the IOGear 2-Port Cinema 4K KVM does not work with this monitor, either having the switch feed into the monitor via a bidirectional DP-to-USB-C cable or the Huawei VR2 cable. The KVM switches the input from the Mac to the PC but never is able to switch the input back to the Mac, no matter what combination of cables I use. Both the PC and the Mac individually are able to drive the monitor directly and each can drive the monitor through the switch as well. I suspect the problem is due to how the KVM handles switching the USB data so trying a different model.
 
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edanuff

macrumors 6502
Original poster
Oct 30, 2008
355
94
Tried two other brands of KVM and different cable combinations. Each time the switching process resulted in the monitor not waking up half the time. At this point, I do not think it's possible to reliably use a KVM to solve the lack of multiple inputs on the LG monitors. Either plan on plugging and unplugging cables or stick with a different brand.
 
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