Thunderbolt Display Extension Cable?

abaybay · Jan 6, 2012

Hello- I just purchased a 27" Thunderbolt display. It looks lovely, especially compared to my 30" Cinema display, which looks quite outdated in comparison. Anyways, I'm using it in a music studio, and am connecting a 2011 MBP 15". I really need to keep the laptop close to one of my racks, which is just out of reach of the cable. The cable is seemingly hardwired into the display. Does anyone know of a 3rd party cable which works to extend the thunderbolt display cable provided?

I've managed to find a couple after googling, but one of them says it is not compatible with the thunderbolt display, and another isn't really specific enough. If someone knows of one which 100% works, I'd be really grateful to have that peace of mind before placing the order. Ideally, I'd love for the cable to extend both the power source and the thunderbolt display connection, but that is in an ideal world, which I'm sure does not exist

Thanks for your help,
-AB

Lennyvalentin · Jan 7, 2012

TB, even after almost a year, is still in its infancy due to only Apple supporting the standard so far. Thus, esoteric stuff like extension cables and whatnot don't really have a market (to a large extent because macheads tend to accept and adjust to whatever hoops Apple make them jump through...

)

You could "fake" an extension yourself by needlessly purchasing another thunderbolt device and plugging it inbetween your computer and monitor. Such as the Lacie Little Big Disk, for example. It'd be the world's most expensive monitor extension cable, but hey... Maybe you'll find use for the extra storage too somehow!

Maybe as backup space, for example.

(You can't have too many backups of anything that is important to you.)

dolphincode21 · Jul 23, 2012

Not sure if you already resolved this, but I had a similar issue with the length of the hardwired cable. I purchased a 2 meter TB cable from Apple and ran it from my MacBook Air to the extra thunderbolt port on the display. It works fine.

One note, the built-in thunderbolt display input cable does split off power into the magsafe adaptor. So by using the thunderbolt expansion port on the display to actually drive the display, you won't be able to use any additional peripherals that require power from the thunderbolt cable.

flynz4 · Jul 23, 2012

dolphincode21 said:
Not sure if you already resolved this, but I had a similar issue with the length of the hardwired cable. I purchased a 2 meter TB cable from Apple and ran it from my MacBook Air to the extra thunderbolt port on the display. It works fine.

One note, the built-in thunderbolt display input cable does split off power into the magsafe adaptor. So by using the thunderbolt expansion port on the display to actually drive the display, you won't be able to use any additional peripherals that require power from the thunderbolt cable.

If you connect to the "TB port" instead of the "pigtale", then as you state... it will work. Since the pigtale is unpowered, you cannot attach a "bus powered" TB device, but you can attach a "self powered" TB device. From that point forward... you can connect a "bus powered" TB device further down the chain. Each powered device seems to provide the power to the downsteam chain.

/Jim

MNT · Jul 23, 2012

dolphincode21 said:
Not sure if you already resolved this, but I had a similar issue with the length of the hardwired cable. I purchased a 2 meter TB cable from Apple and ran it from my MacBook Air to the extra thunderbolt port on the display. It works fine.

I've done this too on a few occasions now where the built-in cable wasn't long enough to reach to where I wanted to place my MacBook Pro. I've been thinking about the length of the built-in cable ever since I got the display; it's almost comically short especially if you assume that eventually the Mac Pro will get Thunderbolt and be expected to connect to these displays.

nexx27 · Aug 30, 2012

Question about dual monitor

flynz4 said:
If you connect to the "TB port" instead of the "pigtale", then as you state... it will work. Since the pigtale is unpowered, you cannot attach a "bus powered" TB device, but you can attach a "self powered" TB device. From that point forward... you can connect a "bus powered" TB device further down the chain. Each powered device seems to provide the power to the downsteam chain.

/Jim

The "pigtale" cable will be short to reach my mac mini. My question is, if I buy two TB Displays, Can I use the TB port on the 1st display to connect to the mac mini and the pigtale on the 1st display to connect to the 2nd TB display and then be able to use both displays? (mac mini '11 2.5ghz)

Can anybody please check that this actually works?

Remmy70 · Dec 31, 2012

update?

I've just purchased a Mac Mini + 27" Thunderbolt display, but I'd like to keep the MacMini a few feet away from the display and the cable attached to the display is not long enough for my purposes.

Can anyone post an update on the availability of thunderbolt extension cables? I understand Apple now sells a ' Thunderbolt cable ' (2 mtrs), can this be used? I still think it's pretty expensive, about $50. Any replies are appreciated!

waw74 · Dec 31, 2012

Remmy70 said:
I understand Apple now sells a ' Thunderbolt cable ' (2 mtrs), can this be used? I still think it's pretty expensive, about $50. Any replies are appreciated!

If only 3 people hadn't already answered that question 5 months ago.

dolphincode21 said:
I purchased a 2 meter TB cable from Apple and ran it from my MacBook Air to the extra thunderbolt port on the display.

MNT said:
I've done this too on a few occasions

flynz4 said:
If you connect to the "TB port" instead of the "pigtale", then as you state... it will work.

CWallace · Dec 31, 2012

Intel has approved fiber-based TB cables out to 30m and they are compatible with current Apple products: https://forums.macrumors.com/threads/1517410/

No price as of yet, but I expect it will not be cheap.

meyem5 · Feb 24, 2015

Hi all,

This post is a bit old now, but I happen to find myself in the same situation. I am planning on getting a Thunderbolt Display 27" to use it as a second display for my iMac, but due to layout issues, I have to place the two about 2 meters apart.

I was searching for solutions to this (given the ridiculous length of the built-in thunderbolt cable plus the frustrating lack of choices offered by apple to sort it out, for instance by allowing you to replace the cable by a longer one, or selling thunderbolt extenders).

My concern is whether I could indeed use the thunderbolt port instead of the built in cable, and still preserve the functionality of the display as far as connectivity goes (use of all the USB, FW and Ethernet ports).

I see from below quoted posts that this seems to be kind off possible, but with limitations:

dolphincode21 said:
Not sure if you already resolved this, but I had a similar issue with the length of the hardwired cable. I purchased a 2 meter TB cable from Apple and ran it from my MacBook Air to the extra thunderbolt port on the display. It works fine.

One note, the built-in thunderbolt display input cable does split off power into the magsafe adaptor. So by using the thunderbolt expansion port on the display to actually drive the display, you won't be able to use any additional peripherals that require power from the thunderbolt cable.

Dolphincode, is it that if I use a thunderbolt cable to connect the display to my iMac I will not be able to use the other ports integrated in the display (USB, FW and Ethernet) at all, or just id the peripheral I wish to connect requires bus power??

flynz4 said:
If you connect to the "TB port" instead of the "pigtale", then as you state... it will work. Since the pigtale is unpowered, you cannot attach a "bus powered" TB device, but you can attach a "self powered" TB device. From that point forward... you can connect a "bus powered" TB device further down the chain. Each powered device seems to provide the power to the downsteam chain.

/Jim

Jim, what do you actually mean by "the pigtale is unpowered"?

My understanding is that the bus powering from the display to peripherals via the built in ports will actually come from the display main supply, so do not understand why the fact that the pigtale cable is unpowered would link to the bus power not being possible...

Many thanks in advance!!

dyt1983 · Feb 24, 2015

edit: To remove personally identifying information not relevant to the thread.

meyem5 · Feb 24, 2015

dyt1983 said:
If you don't have any mechanical/electrical ability, this suggestion is not for you, but it did work for me. I have one TB display that is mounted a fair distance from a Mac Mini. I needed a TB port on the display for other things and wanted it all to work as original for accessories and possible future devices I didn't consider (since the Mini was less accessible). Since it is hooked to a desktop I did not need the MagSafe power. I replaced the TB cable in the display with a longer one. Getting to the port inside isn't too bad if you've opened iMacs before (suction cups for glass, 12 or so torx screws, some cable unplugging). The port on the logic board of the display is a regular connector under a plastic housing. Disassembling the housing lets the cable come out easily and be replaced with a longer one. Fashion a grommet and run it through the original hole, and you now have a longer cable and don't have the extra unused MagSafe.

----------

If you use a separate cable to connect the display to computer through the TB port on the back of the display, the (now unused) cable coming out of the display will not provide power to bus-powered devices, e.g. if you hook a portable TB hard disk up to the pigtail it will not operate.

Many thanks for your reply!

I am not a very handy person with electronics, but will consider giving it a try with some help.

On the other hand, I am not sure i quite get what you mean about the pigtail cable yet. Do you mean that the thunderbolt port cannot provide bus power, or that if I use the TB port the pigtail cable cannot power anymore? Itf it is the latter, Why is that?

in any case, my main question remains to be: If I use the TB port to directly connect the display to the iMac, will the 3USBs, the FW and the Ethernet ports transfer data normally to the iMac (irrespective of the fact that it may not have the ability to provide bus power)?

many thanks again

dyt1983 · Feb 24, 2015

edit: To remove personally identifying information not relevant to the thread.

rebby · Feb 24, 2015

meyem5 said:
in any case, my main question remains to be: If I use the TB port to directly connect the display to the iMac, will the 3USBs, the FW and the Ethernet ports transfer data normally to the iMac (irrespective of the fact that it may not have the ability to provide bus power)?

I think that I'm following the premise of your question but, if I'm not, please forgive me.

By design the TBD has 2 TB connectors;

Pigtail/Magsafe -> TBD -> TB_Port

Apple's "intention" was that you'd connect your devices like this;

(scenario A) = Computer -> Pigtail/Magsafe -> TBD -> TB_Port -> Other_TB_Accessory

but, you CAN connect it like this;

(scenario B) = Computer -> TB_Port -> TBD -> Pigtail/Magsafe -> Other_TB_Accessory

Under "scenario A", everything works as you'd expect. The USB/Ethernet/FW800 ports all work as well (I've tested all but the FW ports). You can also run devices that expect power from the TB bus (such as TB powered 2.5" disks).

Under "scenario B", most things work as you'd expect. The USB ports DO work, I've tested these and use them often (this is how I connect one of my TBDs to my nMP). The Ethernet/FW800 ports also present to the OS so I'd expect them to work as well but have not personally tested them. However, the downstream TB devices will NOT receive TB bus power. So, that bus powered disk that worked just fine in "scenario A" is NOT going to work in "scenario B" unless you can provide external power for it (disclaimer, I have not personally tested bus powered devices but this is well documented here and elsewhere).

Is that what you were asking? Does my reply answer your initial question?

meyem5 · Feb 24, 2015

dyt1983 said:
I found a teardown on ifixit at https://www.ifixit.com/Teardown/Apple+Thunderbolt+Display+Teardown/6525 however they caution that teardowns should "not be used as disassembly instructions". However, the TB display is pretty simple. Normally the disassembly instructions will have warning for pitfalls where connectors are fragile or difficult to remove. The teardowns don't have such warning, but being cautious and using common sense helps.

For instance, the front glass... it's common sense, but usually a warning helps: place the glass somewhere safe where it won't fall or be sat on and broken. I also like to put it inside down so that it doesn't collect as much dust. When reassembling, the glass should be very clean or you'll see the dust and it will bother you. Things like that.

If you use the port to connect the display to the computer (v. the pigtail), the pigtail will not provide power. The cause is probably that the board in the display is configured not to provide power to the pigtail; the reason is unknown for sure, but can be surmised: Apple intended the pigtail to be connected to a computer and providing bus power to a computer would not be useful.

That is an excellent question. The TB bus power is independent of the USB/FW bus power, so if they work at all they should provide the power. My guess is that since the display works, the ports will also work. Unfortunately I would not say that with conviction until it was proven to work, which will require someone plugging it in that way. I'll try to do so when I can get everything closer together.

Wow, great explanation!. Thanks a lot for taking the time to reply. So kind of you.

Then if you have the chance to check whether the ports would work via the TB port (pigtail disconnected), that'd be great. Otherwise, I'll try and see if I find someone I know who owns one to test it for me.

have a great day!

rebby · Feb 24, 2015

meyem5 said:
Then if you have the chance to check whether the ports would work via the TB port (pigtail disconnected), that'd be great. Otherwise, I'll try and see if I find someone I know who owns one to test it for me.

Check post 14, I can confirm that at least some of them work.

dyt1983 · Feb 24, 2015

edit: To remove personally identifying information not relevant to the thread.

meyem5 · Feb 25, 2015

rebby said:
I think that I'm following the premise of your question but, if I'm not, please forgive me.

By design the TBD has 2 TB connectors;

Pigtail/Magsafe -> TBD -> TB_Port

Apple's "intention" was that you'd connect your devices like this;

(scenario A) = Computer -> Pigtail/Magsafe -> TBD -> TB_Port -> Other_TB_Accessory

but, you CAN connect it like this;

(scenario B) = Computer -> TB_Port -> TBD -> Pigtail/Magsafe -> Other_TB_Accessory

Under "scenario A", everything works as you'd expect. The USB/Ethernet/FW800 ports all work as well (I've tested all but the FW ports). You can also run devices that expect power from the TB bus (such as TB powered 2.5" disks).

Under "scenario B", most things work as you'd expect. The USB ports DO work, I've tested these and use them often (this is how I connect one of my TBDs to my nMP). The Ethernet/FW800 ports also present to the OS so I'd expect them to work as well but have not personally tested them. However, the downstream TB devices will NOT receive TB bus power. So, that bus powered disk that worked just fine in "scenario A" is NOT going to work in "scenario B" unless you can provide external power for it (disclaimer, I have not personally tested bus powered devices but this is well documented here and elsewhere).

Is that what you were asking? Does my reply answer your initial question?

rebby said:
Check post 14, I can confirm that at least some of them work.

Many thanks for your post, rebby. I had overlooked it !

It is very useful piece of info. I think I understand everything now. I seems pretty logic, actually.

Thanks again!

rebby · Feb 25, 2015

meyem5 said:
Many thanks for your post, rebby. I had overlooked it !

It is very useful piece of info. I think I understand everything now. I seems pretty logic, actually.

Thanks again!

Great! It's a little confusing how they have that working. I still don't fully understand the WHY, just the HOW.

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