mac pro "thunderbolt to displayport" asus PB278Q issue

wildwill

macrumors newbie
Original poster
Jun 10, 2008
20
0
Hello all.

I have a 2014 Mac Pro which I have a 6ft mini displayport to to displayport cable connected to a asus PB278Q. This works fine but I want to move the Mac Pro off my desk and onto a shelf, so got a 15ft mini displayport to to displayport cable and when I connect it up the screen does not see any input on the display port.

Any ideas?

Will
 

martinm0

macrumors 6502a
Feb 27, 2010
563
25
Hello all.

I have a 2014 Mac Pro which I have a 6ft mini displayport to to displayport cable connected to a asus PB278Q. This works fine but I want to move the Mac Pro off my desk and onto a shelf, so got a 15ft mini displayport to to displayport cable and when I connect it up the screen does not see any input on the display port.

Any ideas?

Will
I'm going to guess the cable is bad?? It seems like displayport cables can run much longer than that length, so I expect it should work. Have you tried plugging it into another Thunderbolt port? Was it a decent quality cable? Might need to return it and get a new one is possible.
 

wildwill

macrumors newbie
Original poster
Jun 10, 2008
20
0
I'm going to guess the cable is bad?? It seems like displayport cables can run much longer than that length, so I expect it should work. Have you tried plugging it into another Thunderbolt port? Was it a decent quality cable? Might need to return it and get a new one is possible.
Well funnily enough this is the not my first cable that this has happened with. I ordered a Cable Matters cable from Amazon (link below) and have had the same issue with both. I also tried using a different port on the machine with same result.

http://www.amazon.com/gp/product/B00C7RL33M/ref=oh_aui_detailpage_o00_s01

But this evening i just got home with a 3rd cable and this one seems to work ok!

I think this weekend i will try doing some more testing with the other cables before i return them :)

On a side note what is the max lenght you have heard working?
 

martinm0

macrumors 6502a
Feb 27, 2010
563
25
Well funnily enough this is the not my first cable that this has happened with. I ordered a Cable Matters cable from Amazon (link below) and have had the same issue with both. I also tried using a different port on the machine with same result.

http://www.amazon.com/gp/product/B00C7RL33M/ref=oh_aui_detailpage_o00_s01

But this evening i just got home with a 3rd cable and this one seems to work ok!

I think this weekend i will try doing some more testing with the other cables before i return them :)

On a side note what is the max lenght you have heard working?
Great to hear the new cable works.

I found this info on Datapro.com:

"DVI offers no audio support; DisplayPort offers full digital audio support (up to eight channels) in the same cable as video. DVI is crippled by its maximum spec length of 5 meters, while DisplayPort is designed for up to 15 meters."