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Multi-screen KVM and connecting PC & Mac to two monitors

Discussion in 'KVM' started by jkah, Dec 19, 2018.

  1. jkah

    jkah Guest

    I understand that a KVM can wire a PC and Mac to a monitor, but, how can I wire a PC and Mac to two screens? Objective is NOT to see PC on monitor 1 and Mac on monitor 2, no, rather, to be able to switch between the PC and the Mac and be able to use two screens for each. My Mac is the new Mac Mini 2018 with three Thunderbolt ports. My PC is the HP spectre x360 with two Thunderbolt ports.
  2. KVMGalore Expert

    KVMGalore Expert Staff Member

    Hello jkah,

    Thank you for reaching out on our HelpCenter.

    Important note: To continue this discussion - please respond via KVMGalore HelpCenter thread, NOT via e-mail.

    Yes, you want to create an extended desktop an be able to use it for each one of your machines (Mac and PC) via a KVM switch.

    You'll need a 2-port multi-screen KVM switch to accomplish this. You may also want to look at 4-port multi-screen KVM switches because 2-port models are fairly limited in the marketplace.

    Please provide some additional information regarding the video interfaces you have:
    1) Does your Mac have Thunderbolt 2, or Thunderbolt 3?
    2) Does your Mac have any other video interface other than Thunderbolt?
    3) Does your PC have Thunderbolt 2, or Thunderbolt 3?
    4) Does your PC have any other video interface other than Thunderbolt?
    5) What video interfaces do you screens support?
  3. jdkah

    jdkah Guest

    Thanks for the reply. In answer to your questions:
    1) & 2) The Mac Mini 2018 has 4x Thunderbolt 3 USB-C ports; 2x USB-A 3 ports; HDMI 2.0 port
    3) Has 2 USB 3.1 Gen 2 (Type-C, HP USB Boost, Thunderbolt), one USB 3.1 Gen 1 (Type-A)
    4) No other video interface
    5) I have not yet purchased my screens, thus, I can buy whatever is needed.

    I look forward to your recommendations. Another expert told me that it is impossible to take a PC and Mac and using KVM, be able to enjoy using two screens for the PC and then switch and enjoy using two screens for the Mac.
  4. KVMGalore Expert

    KVMGalore Expert Staff Member

    Hello again, John:

    Thanks for getting back with this info.
    To create an extended desktop - especially when working with a KVM switch - each one of your computers must have 2x video outputs (learn more about multi-screen KVM switches here).
    While Thunderbolt 3 and USB Type-C can drive video, it is better to utilize dedicated video ports. And so, we'd like to reconfirm the following:

    A) Only one HDMI port?

    B) Does your PC indeed have no other video ports at all?

    They are wrong! KVM switches are hardware solutions and they don't care about operating systems, and so they don't care if the video signals )and USB signals) are coming from a Mac or a PC. Learn more about KVM switches here.

    Awaiting your response.

    Important note: To continue this discussion - please respond via KVMGalore HelpCenter thread, NOT via e-mail.
  5. jdkah

    jdkah Guest

    Thanks for the continued conversation on this. Feels like I am venturing into some great unknown for this setup.
    A) Yes, only the Mac mini 2018 has a HDMI port.
    B) The HP Spectre x360 is one year old, it is a slim, convertible PC/tablet layout. Specs I quoted are taken directly from the device description, just as I said, 2 USB 3.1 Gen 2 (Type-C, HP USB Boost, Thunderbolt), 1 USB 3.1 Gen 1 (Type-A).

    A tech guy from IOGEAR wrote me and told me this:
    "I have tried your setup here in our office I only got the picture to show up once and then I could not get it going so you can try different adapter but my opinion is that its not going to be stable enough to work.
    Because if the adapters you have are not going to be stable enough them it will be pointless to have it.
    I don't have another device that will accommodate your setup."

    I have worked with a set up with this same HP I am describing for one year successfully using two screens using the StarTech.com Thunderbolt 3 to Dual HDMI adapter-4k 30Hz. This peripheral device has one Thunderbolt wire which I connected to the HP Spectre Thunderbolt output, and the StarTech adapter has two HDMI ports which I used to connect my two screens. It worked great.

    I have since retired from that job, and setting up my home office, thus, do not yet own any screens, (I'm typing this from my mac). I'm going to guess I could connect the same StarTech device to my new mac mini and use two screens (again, can't experiment because I don't own the two screens yet).

    Silly me - - I thought it would be possible to buy the two screens, then stack the Mac Mini and the HP Spectre and run them both through a KVM, and somehow use the PC enjoying two screens, and then switch, and use the mac with two screens.

  6. jdkah

    jdkah Guest

    May I also add - - - the people at Tripp-Lite, I believe a KVM manufacturer said to me, like the people at IOGEAr: "Unfortunately, we do not have a KVM to accommodate those devices. Let me know if you have additional questions."
  7. KVMGalore Expert

    KVMGalore Expert Staff Member

    Hello again, John:

    Don't despair! Your requirement is indeed achievable, but it cannot get magically accomplished out of thin air.

    A dual-view KVM switch requires 2x identical video inputs per port (per computer) in order to be able to send two video outputs (of the same format) to your 2-screen extended-desktop console. The problems in your case is that a dual-view KVM switch supporting Thunderbolt 3 probably doesn't exist in the marketplace.

    And so you must use adapters to bring all your video inputs and outputs to a level playing field that a KVM switch can handle. That being said - using adapters always involves a 'stability risk', because adapters don't always utilize the complete spectrum of features which are part of a native video specification.

    Since you already have good experience with the StarTech Thunderbolt 3 to Dual HDMI adapter being used directly on your HP Spectre without a KVM switch, it is very likely it will work well interfacing with a KVM switch as well.

    Hope this helps!
    We welcome your questions - please come back and ask us anything, anytime, or just offer your feedback.
  8. jkah

    jkah Guest

    Thank you for your advice. I will try to make this work.
  9. jkah

    jkah Guest

    The question remains, if I had two manufacturers of KVM switches already tell me they do not manufacture a switch that supports my plan, where do I turn to find one? Seems this is what I will wind up doing: when I want to use the PC on two screens, plug the StarTech adapter into the PC. When I want to use the mac on two screens, unplug from the PC and plug into the Mac. Forget about using a KVM switch.

    This is a clunky and archaic way of doing things, but KVM designers have not figured out that in the business world many of us use two screens. The Mac is brand new and the PC is one year old, thus, not talking about old technology.
  10. KVMGalore Expert

    KVMGalore Expert Staff Member


    We hear your frustration - you are absolutely correct.

    KVM switches supporting two screens have been available for quite some time. It is the support of mixed video formats that KVM-switch manufacturers are being slow to address. But with the convergence of the technology, e.g. Thunderbolt 3 and USB-C using the same connector, having the video being driven through the same connector at data, we hope they will soon come around.

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