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K3mp

macrumors 6502
Original poster
May 4, 2008
335
0
S.E. Louisiana
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
 

SnowLucas

macrumors member
Feb 19, 2015
71
105
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.
 

Dr Charter

macrumors 6502
Feb 26, 2011
277
8
Oklahoma
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.

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?
 

ColdCase

macrumors 68040
Feb 10, 2008
3,359
276
NH
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."
 
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Dr Charter

macrumors 6502
Feb 26, 2011
277
8
Oklahoma
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.
 

Dr Charter

macrumors 6502
Feb 26, 2011
277
8
Oklahoma
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.
 

JoeFkling

macrumors regular
Feb 3, 2013
169
61
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.
 

paulrbeers

macrumors 68040
Dec 17, 2009
3,963
123
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.

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.
 

taenzerme

macrumors newbie
Oct 20, 2011
15
0
Bonn, Germany
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
 

JTToft

macrumors 68040
Apr 27, 2010
3,447
796
Aarhus, Denmark
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.

- 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.
 

ColdCase

macrumors 68040
Feb 10, 2008
3,359
276
NH
Is there any way to use 2 display port displays at 2560x1440 connected to one thunderbolt dock (so I get ethernet and usb3 ports)?

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
 
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Dandu

macrumors regular
Jan 23, 2009
118
14
Thanks for The reply.

Am I wrong or doesn't HDMI only support up to 1080p?

That depends on the version. HDMI 1.4 (which is pretty standard) supports up to 3840x2160 at 30Hz.

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.
 

JTToft

macrumors 68040
Apr 27, 2010
3,447
796
Aarhus, Denmark
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.

- 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...
 

StianSylta

macrumors member
Jun 11, 2013
38
45
Norway.
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.
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.
WHaT?

Can you confirm that you can use a Thunderbolt Dock to connect a MacBook to an iMac with Target Display Mode?
 

Cougarcat

macrumors 604
Sep 19, 2003
7,766
2,553
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.
 

cuestakid

macrumors 68000
Jun 14, 2006
1,775
44
San Fran
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.
 

pdwalker

macrumors newbie
Dec 23, 2010
8
0
I have used the OWC Thunderbolt 2 dock with 3 external monitors successfully for years without problem.

1 x 27" 2560x1440 iMac as external thunderbolt display in target display mode
1 x 25" 2560x1440 dell hdmi monitor
1 x 23" 1650x1050 lg monitor via usb3->hdmi adapter

The laptop is a 2011 17" MBP.

The dock also has Gb ethernet connected, and 2 USB3 external drives, and I've never had an issue with speed or performance.
 
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