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What cables do I need for the Level 1 Techs USB-C KVM switch?

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l1kvm
#1

Hi everyone! I just received the USB-C KVM switch and can’t wait to start using it. I’m not super knowledgeable about cables so I was hoping y’all could help me out with figuring out what I need to connect everything. I’ll be connecting a 2017 MacBook Air with a Thunderbolt 2 port, a desktop computer with a mini-displayport, and a monitor with DVI-IN port to the KVM switch.

What cables would I need to set everything up? Would the following setup be correct?

  • Two Thunderbolt2 to USB-C cables (to connect the MacBook Air and the desktop to the switch)
  • One DVI to DisplayPort cable (to connect the monitor to the switch)

Any help would be greatly appreciated!!

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#2

hmm… I am not sure these adapters are going to work this way for you… generally you can move up, but not down, in connector types. There are some exceptions.

You miiight have been better off with the hdmi kvm, maybe.

Most adapaters are one way… meaning they take a USBc signal in and give you display port out.

You can’t swap it so that it is display port in, then usbc out… that’d be weird.

I am working on a board that accepts DP and USB3 in and provides USBc out (muahahaha) but that’s not ready. At any rate, prettymuch only a DP monitor will work for the KVM output.

There is no signal translation in the kvm. It’s just a switch. It would be crazy expensive if it could accept any type of input and provide any type of output because the digital signals for all these are actually different.

A thunderbolt2 dock that has a USBc+DP output is probably what you need on that side. And some sort of native-displayport-supporting monitor for the output?

I might not have unpacked what you were asking for correctly though.

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#3

Did you already buy an L1T USB-C KVM?

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#4

I don’t think I explained my setup very well, let me try again.

I have a MacBook Air with Thunderbolt 2 port. I am using a mini-DP (connected to the Air) to USB-C (connected to the KVM switch) cable. So this is mini-DP out to USB-C in.

For my desktop computer, I’m again using a mini-DP (connected to the desktop) to USB-C (connected to the KVM switch) cable. So again this is mini-DP out and USB-C in.

Finally, my monitor is connected to the KVM switch using a DVI (connected to the monitor) to mini-DP cable (because this is the cable I had on hand) with a mini-DP to DP adapter (the adapter is connected to the KVM switch). So this is DP out.

I tried the setup and it’s not working, so I know I’m doing something wrong. Any ideas why it’s not working and how I can make it work?

To answer your question Grokas, yes I already bought and received the L1T USB-C KVM.

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#5

Okay, so what adapter are you using that goes from mini-dp to usbc?

Mini dp doesn’t carry a USB signal so you’d have to have minidp + usb on one end, for usbc on the other?

Sometimes you see a DP dongle that will take a DP signal then turn it into DVI, but going the other way is not the same… I don’t think the KVM supplies power for that type of dongle though even if the signals worked properly somehow.

These adapters are (most probably) not like math where it is transitive. X+Y != Y+X …

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#6

I see, so a mini-DP to USB-C cable isn’t sufficient and I need an adapter? Would a thunderbolt cable work instead since it carries a USB signal? If so, I would need two Thunderbolt 2 to USB-C cables, is that correct?

For the monitor, I’m not sure I completely understand what you’re saying. If the display information is fed to the KVM, and the KVM feeds this info to the monitor, then it does essentially take a DP signal and turn it into DVI, no? I don’t think it goes the other way around. The KVM has a DP out port and the monitor has a DVI in port.

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#7

So a DP to DVI adapter is an active device. It needs power. Usually the DP connector supplies power to power devices like this… I think thats pin 20. I forget.

So the KVM probably doesn’t supply power to convert the signal.

There are also passive DP to DVI adapters where the video card senses you are trying to use dvi and it does dvi signaling, but over the DP connector,

With the kvm, it will handshake as DP though so the video card probably won’t drop to dvi mode if you have a passive type adapter.

I am not aware of any thunderbolt 2 to usb c cables. Thunderbolt 2 doesn’t carry usb as far as I’m aware. You might possibly go thunderbolt 2 into a docking station of some type. That would provide DP and USB but then you still need to adapt USB and DP to USBC which combines both signals on one cable.

I would start by testing the kvm with the display and a device like a chromebook with a usbc cable that can carry displayport (or a thunderbolt cable). Juts to confirm if the dvi adapter will actually work… I suspect not, though because it doesn’t work that way… its not the kvm is just that you have to have active electronics to translate all these signal types. Its not just a matter of wiring…

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#8

Thanks Wendell for taking the time to explain all that. It sounds like I got the wrong KVM for my purposes.

Would it make more sense to get the HDMI KVM?

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#9

Yes.

If you’re looking to sell that KVM btw, I’m interested :smile:

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#10

I would guess yes, hdmi is probably better, for your situation. Do all your devices have hdmi? does your monitor have hdmi in? because dvi and hdi are really close electrically for 1st gen but they diverge quite a bit when you need to support resolutions over 1080p.

there are actually powered adapters that take other signals and turn them into hdmi, too, so more flexibility.

I use a kvm with my dell laptop and a thunderbolt dock, and it works great. With the new usbc kvm I don’t need a dock anymore. Otherwise I had to use usbc to usb + usbc to dp which is a PITA. Plus power. 3 cables into the laptop.

but I only need one cable from my desktop with an rtx 2070 because its got usbc out.

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#11

I’m using this setup at work and I think the monitor I have there is really old, might be from 2007. There’s no HDMI in, just DVI and VGA. The maximum resolution is 1080p, so the HDMI KVM should be ok right?

Grokas, I might keep the USB-C model for future use but I’ll think about it :slight_smile:

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#12

the best use of the usbc model is with phones like the galaxy s9/10 that can become like android tablets when “docked” it is cool AF.

using your phone like a chromebook is just the coolest thing ever that I had no idea I’d actually enjoy.

It “might” work but it might not with the old monitor… its hard to say.

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#13

Would the USB-C model be a good choice for newer laptops that have USB-C ports?

I just checked and there’s another monitor at work that I can use and which has an HDMI in port. So all I would need for an HDMI KVM with my current setup would be 2 mini-DP to HDMI cables (to connect the laptop/desktop to the KVM) and 1 HDMI to HDMI cable (to connect the KVM to the monitor. Does that seem correct?

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#14

FWIW:

The Apple thunderbolt 2 to thunderbolt 3 adapter is 2-way with the caveat that it will not power bus-powered tb 3 devices (so it should work for your inputs).

For the dp to dvi conversion, you’ll want to look for something that’s more like a box with its own power source than a dongle. It’ll be a somewhat obscure and expensive part.

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#15

Could you send me a link to a thunderbolt 2 to thunderbolt 3 adapter? The only one I could find is tb2 female to tb3 male, whereas I would need the adapter to be male to male.

For the monitor side of things, I can get my hands on an HDMI monitor so that should connect easily to the DP port on the KVM.

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#16

Add Male to Male cable to that one?

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#17

Makes sense. I was trying to minimize the number of cables/adapters ><

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#18

if you didnt see it they probably dont have any other one, but that is a good goal always

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#19

Yep.

Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter

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