Trouble W/ multiple monitors OWC Thunderbolt 2 dock

Discussion in 'Mac Accessories' started by K3mp, Apr 1, 2015.

  1. K3mp macrumors 6502

    Joined:
    May 4, 2008
    Location:
    S.E. Louisiana
    #1
    Hey all,

    I have a Thunderbolt 2 dock form OWC connected to a late 2013 retina macbook pro. I also have and LED cinema display that uses mini display port along with a monitor that uses HDMI. The rMBP will drive both of the displays when one is connected to the dock and the other is connected directly to the rMBP but not when they are both connected to the dock. Anything I can do to fix this? Thanks
     
  2. SnowLucas macrumors member

    Joined:
    Feb 19, 2015
    #2
    This is true of all thunderbolt docks. Two monitors from one thunderbolt connection is possible if one monitor is a thunderbolt monitor only.

    You cannot use a dock to do what you are trying to do. Two docks supposedly will allow two monitors on the same chain. Or more realistically plug one directly into the laptop.
     
  3. ColdCase macrumors 68030

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    Feb 10, 2008
    Location:
    NH
    #3
    Yes, its a well known and well discussed technical limitation.
     
  4. Dr Charter macrumors 6502

    Joined:
    Feb 26, 2011
    Location:
    Oklahoma
    #4
    I might be misunderstanding the issue here (or it might be an issue with this particular dock) but I use an TB1 Elegato dock to drive two monitors with my MacBook Air. It works flawlessly. One uses a DVI-HDMI adapter and the other uses the DVI to mini-displayport adapter. I plug both into the dock and the dock into the Thunderbolt port. Is there some other factor in the OP's case that I am missing?
     
  5. ColdCase, Apr 7, 2015
    Last edited: Apr 7, 2015

    ColdCase macrumors 68030

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    #5
    Interesting.The following Elgato support article says you can't do what you are doing as the DVI-HDMI will take precedence or the DVI-DP will take precedence... video to the monitor without precedence gets blocked... but I dunno.

    http://help.elgato.com/customer/por...hunderbolt™-dock-and-multiple-display-support

    "There can be up to two DisplayPort signals available on the Thunderbolt™ bus, depending on the Mac or PC.

    When the DisplayPort signals come from the computer over Thunderbolt™, and travel into the Elgato Thunderbolt™ Dock, one of them is demultiplexed. That DisplayPort signal is ready to be used.

    The demultiplexed DisplayPort signal is translated by the Elgato Thunderbolt™ Dock into HDMI. That leaves one DisplayPort signal still multiplexed in the Thunderbolt™ signal, for later use in the Thunderbolt™ chain.

    That second DisplayPort signal can only be demultiplexed by another Thunderbolt™ device, like the Apple Thunderbolt Display, or by another Elgato Thunderbolt™ Dock.

    If you connect a DisplayPort monitor to the Thunderbolt™ connection when the HDMI port is in use, the DisplayPort monitor will not light up. In this case, only Thunderbolt™ signaling is available at the Thunderbolt™ connection, which the DisplayPort monitor does not understand.

    When you try to connect two non-Thunderbolt™ monitors to the Elgato Thunderbolt™ Dock, you can either get a signal over the HDMI port, or via DisplayPort, but not both at the same time.

    If you choose to use a HDMI device, then one multiplexed signal remains, associated with the Thunderbolt™ port, available for Thunderbolt™ devices only.

    If you choose DisplayPort (via the Thunderbolt™ port), then the Thunderbolt™ bus is terminated, when it comes to display signals. The DisplayPort monitor will work, but the HDMI port will not."
     
  6. Dr Charter macrumors 6502

    Joined:
    Feb 26, 2011
    Location:
    Oklahoma
    #6
    That just hasn't been my experience. I'll post a pic in the office tomorrow but I have two small Dell monitors hooked up to the dock with one cable to the computer. It works fine.

    If I couldn't use two monitors with a dock, it would defeat the purpose for me. I used it to replace a Mac Mini that had been hooked up to these monitors.
     
  7. Dr Charter macrumors 6502

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    Feb 26, 2011
    Location:
    Oklahoma
    #7
    I figured out why it worked. I had forgotten that the second monitor was plugged into a LaCie Little Big Disk. Apparently daisy chaining the second monitor to the LaCie drive and plugging that drive into the dock is what made it work. Sorry to add confusion to the situation but it seems like that might be a workaround. It certainly has worked for me.
     
  8. JoeFkling macrumors regular

    Joined:
    Feb 3, 2013
    #8
    I thought that TB was fully backwards compatible to MDP. Bummer

    But as an added bonus for anyone, target display mode works through the TB2 dock. Not sure if this is news, but everything I have read says that the TDM iMac has to be directly connected. This allows me to run the HDMI monitor and the iMac from 1 TB port.
     
  9. paulrbeers macrumors 68040

    Joined:
    Dec 17, 2009
    #9
    It is fully backwards compatible. You just can't hook two monitors directly to a single dock. You need two docks or a dock and another thunderbolt device. Just a limitation.
     
  10. taenzerme macrumors newbie

    Joined:
    Oct 20, 2011
    Location:
    Bonn, Germany
    #10
    MBPr 13 Late 2013 - MST?

    Hello guys,

    I hope it's not too late to join the discussion ;-) I am myself planning to retire my old 2009 iMac and work with my MBPr 13 Late 2013 with multiple displays.

    I'd like a setup with 2 x 2560x1440 display port displays and would love to use a Belkin/Elgato/whatever dock to connect only one thunderbolt cable to it on my desk.

    I don't understand how I am supposed to connect 2 displayport displays (let's say the DELL U2715H) when the elgato dock is connected to one tb port.

    Is there any way to use 2 display port displays at 2560x1440 connected to one thunderbolt dock (so I get ethernet and usb3 ports)?

    Best,
    Sebastian
     
  11. JTToft macrumors 68040

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    Apr 27, 2010
    Location:
    Aarhus, Denmark
    #11
    - For that you'd have to use two docks, as described above. Like this:

    MBP -> Thunderbolt Dock 1 -> Display 1 via HDMI and Thunderbolt Dock 2 via TB -> Display 2 via Mini DisplayPort

    Now, the issue comes if you insist on connecting both displays via DisplayPort over just the one Thunderbolt port on your computer. Then you'd need either three Docks (to have two free Thunderbolt ports) or a Dock with at least two available DisplayPort-capable ports.
    I'm not sure either of those things can be done/exist, though.
     
  12. taenzerme macrumors newbie

    Joined:
    Oct 20, 2011
    Location:
    Bonn, Germany
    #12
    Thanks for The reply.

    Am I wrong or doesn't HDMI only support up to 1080p?
     
  13. JTToft macrumors 68040

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    Apr 27, 2010
    Location:
    Aarhus, Denmark
    #13
    That depends on the version. HDMI 1.4 (which is pretty standard) supports up to 3840x2160 at 30Hz.
     
  14. ColdCase, Apr 27, 2015
    Last edited: Apr 28, 2015

    ColdCase macrumors 68030

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    NH
    #14
    I don't think so, I don't recall a dock with a display port (or a pass through and DP) . You would probably need to use both rMBP TB ports. You would connect one display directly to the rMBP and the other to the other port. Insert your choice of dock between one of the displays and rMBP.

    If you insist on one cable, think about using one of those $100 HDMI to DP converters on the dock's HDMI port. You will also need a second TB device, a storage box or another dock, between the dock and second display port monitor.

    rMBP -> dock -> thunderbay -> display port monitor.
    ................|
    .............HDMI
    .............Adapter
    ............DP Monitor
     
  15. Dandu macrumors regular

    Joined:
    Jan 23, 2009
    #15
    It's not a problem with the HDMI itself, it's a problem with the GPU. A Mac with a recent GPU from AMD or NVIDIA can use HDMI 1.4, or a Mac with an Intel HD 5000 or better (i think), but with an Intel HD 4000, it will not work.
     
  16. JTToft macrumors 68040

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    Apr 27, 2010
    Location:
    Aarhus, Denmark
    #16
    - Alright... Which is relevant how?
    The machine in question (13" Late 2013) uses Intel Iris graphics, supports 3840x2160 at 30Hz on its HDMI output, and up to two 2560x1600 displays in addition to its built-in display at full resolution...
     
  17. StianSylta macrumors member

    Joined:
    Jun 11, 2013
    Location:
    Norway.
    #17
    WHaT?

    Can you confirm that you can use a Thunderbolt Dock to connect a MacBook to an iMac with Target Display Mode?
     
  18. Cougarcat macrumors 604

    Joined:
    Sep 19, 2003
    #18
    Did Sierra solve the issue of daisychaining DisplayPort monitors in OS X? When I get a new 13" MBP I want to share a p2415q and an older dell monitor (with a keyboard and mouse) between the MBP and my gaming PC, and I'm wondering what the best way to go about that would be. It seems 4K capable KVMs to share more than one monitor either don't exist or are prohibitively expensive.
     
  19. cuestakid macrumors 68000

    Joined:
    Jun 14, 2006
    Location:
    San Fran
    #19
    It has always been my experience with the OWC dock that, even if the two monitors are on totally different ports(one Mini DisplayPott/TB and one HDMI) It simply won't work. My workaround was to plug the HDMI monitor in directly to my MBP and it works fine.
     

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