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Thunderbolt 2 -> Thunderbolt 3/4

W

Wingsley

macrumors 6502
Original poster
Mar 20, 2014
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MY CURRENT (AGING) HARDWARE:
late-2013 Core i5 iMac, 21.5-inch; 1 TB HDD, 8 GB RAM
currently running MacOS 10.12.6 Sierra, about to clean-install 10.14 Mojave
favorite apps: Office 365, Apple Mail, Safari, FireFox, Chrome, iPhoto, DymoLabel
occasional apps: Final Cut Pro 7, iWeb, Quicken, EpsonScan, etc.

I used to run Adobe Creative Cloud; my ACC subscription was cancelled at the end of a sponsorship for a long-term business project. I am now seeking a new avenue to secure a renewed ACC subscription. I got light-to-moderate use out of Acrobat Pro, InDesign, Illustrator and Photoshop. I want to expand my use of ACC both in terms of how many apps I use and how much skill I have in each.

My aging iMac is obviously wayyyyy out of date. I am still getting lots of miles out of this budget workhorse.

My reason for posting this here today: I am seriously thinking of spending some reserve money to get at least one new or refurbished Apple Silicon-equipped Macintosh computer. Top candidate, at least to start with, would be a Mac Mini. If I bought a Mac Mini **right now** (very tempting), I would get it with 16 GB of RAM and probably ample built-in SSD. It would easily be at least $1,300, not including a Logitech keyboard, mouse and Apple trackpad.

Here's where things get weird:

While I intend to eventually get an external monitor for the new machine, I won't have the budget for it right away. Extra funds, if available, would like go to a new ACC subscription. The solution? iMacs of that vintage have a little-know feature called "Target Display Mode" (TDM), which allows the iMac to be restarted as an external monitor. For the near term, assuming I "push the button" and buy a Mini, I would plug it into the iMac in TDM. Thus, the old iMac would do double-duty as the Mini's external monitor.

Screwy solution, I know, but it should work for the near-term. It's the best way to actually make a commitment to the new silicon and all the current software that runs on it.

Here's where things get weirder...

The old iMac has ThunderBolt 2. The Mini, as with other late-model Apple Silicon computers, uses ThunderBolt 3 / 4. Is there a straight, high-quality cable on the market right now with ThunderBolt 2 male on one end and ThunderBolt 3+ male on the other end? I see Apple has an adaptor dongle, But I want to see if there are any good aftermarket hybrid cables out there. Any suggestions?
 
Juicy Box

Juicy Box

macrumors 604
Sep 23, 2014
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Wingsley said:
The solution? iMacs of that vintage have a little-know feature called "Target Display Mode" (TDM), which allows the iMac to be restarted as an external monitor. For the near term, assuming I "push the button" and buy a Mini, I would plug it into the iMac in TDM. Thus, the old iMac would do double-duty as the Mini's external monitor.
Click to expand...
You will have to rethink your monitor solution.

Target Display Mode doesn't work on the M1 Macs with the TB iMacs that are capable of TDM. Apple disabled it for the M1 for some reason. Probably to sell the Studio Display.

You can use the Mini Display Port iMacs (27" Late 2009 - 27" Mid 2010) that are TDM capable with M1 Macs, but that doesn't help you.
 
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Juicy Box

Juicy Box

macrumors 604
Sep 23, 2014
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Wingsley said:
Screwy solution
Click to expand...
It isn't a screwy solution if it worked. There are plenty of people using their older iMacs in Target Display Mode with their newer Macs. The iMac has a high quality display, wanting to use it as an external display is very understandable.

It just sucks that Apple won't allow it with the M1 Mac. It is also pretty crappy that TDM wasn't added to the new M1 iMac as well.
 
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Juicy Box

Juicy Box

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Sep 23, 2014
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Wingsley said:
I see Apple has an adaptor dongle, But I want to see if there are any good aftermarket hybrid cables out there. Any suggestions?
Click to expand...
AFAIK, only Apple makes a bidirectional adapter.

I have a few of Apple's adapter, but only have used them to connect TB1 Macs to TB3 docks, NVMe drives, etc.

Wingsley said:
The old iMac has ThunderBolt 2.
Click to expand...
Technically, TB1. The Late 2014 models were the first iMacs with TB2.
 
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J

joevt

Contributor
Jun 21, 2012
6,880
4,174
Juicy Box said:
Just this:
www.apple.com

Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter

Effortlessly connect your Mac to a Thunderbolt 2 device with the Apple Thunderbolt 3 Adapter. Buy now at apple.com
www.apple.com

You can sometimes find a good deal for them on eBay.
Click to expand...
You also need a Thunderbolt 2 cable to go with it.
Can an M1 Mac connect to Thunderbolt 1 devices?
Can an M1 Mac do Thunderbolt IP to a Thunderbolt 1 Mac?
The M1 Mac needs to be able to detect the Thunderbolt 1 Mac if there's a chance to make Thunderbolt Target Display Mode work. But yeah, Apple probably didn't update the Thunderbolt Target Display Mode driver to work with the Apple Silicon Thunderbolt controller?
I have done Thunderbolt Target Display Mode from a Mac mini 2018 to a 2013 iMac in macOS 12 Monterey.
 
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W

Wingsley

macrumors 6502
Original poster
Mar 20, 2014
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joevt said:
You also need a Thunderbolt 2 cable to go with it.
Can an M1 Mac connect to Thunderbolt 1 devices?
Can an M1 Mac do Thunderbolt IP to a Thunderbolt 1 Mac?
The M1 Mac needs to be able to detect the Thunderbolt 1 Mac if there's a chance to make Thunderbolt Target Display Mode work. But yeah, Apple probably didn't update the Thunderbolt Target Display Mode driver to work with the Apple Silicon Thunderbolt controller?
I have done Thunderbolt Target Display Mode from a Mac mini 2018 to a 2013 iMac in macOS 12 Monterey.
Click to expand...
I'm confused. I have a late-2013 21.5-inch iMac. If I start it up in Target Display Mode, and connect the old iMac to an M1 Mac Mini running MacOS Monterey via ThunderBolt cable + adaptor, would this arrangement work? Would the old iMac, while in TDM, show the Monterey desktop from the Mac Mini?
 
Juicy Box

Juicy Box

macrumors 604
Sep 23, 2014
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Wingsley said:
I'm confused. I have a late-2013 21.5-inch iMac. If I start it up in Target Display Mode, and connect the old iMac to an M1 Mac Mini running MacOS Monterey via ThunderBolt cable + adaptor, would this arrangement work?
Click to expand...
No, Target Display Mode doesn't work with the TB iMac (like you have) and the M1 Macs.

Wingsley said:
Would the old iMac, while in TDM, show the Monterey desktop from the Mac Mini?
Click to expand...
No, not with Target Display Mode and your current equipment.

There are other solutions, like Screen Sharing, which is built into the OS, and third party solutions, such as Luna Display. But, Target Display Mode will not work with the TB iMacs and M1 Macs.


joevt said:
You also need a Thunderbolt 2 cable to go with it.
Click to expand...
I guess while mentioning additional items that might be needed, Target Display Mode works only with certain Keyboards.

I am a fan of Apple older plastic, full-sized keyboards from the early to mid 2000's, and I hate the aluminum ones. But, I cannot get Target Display Mode to activate with older keyboards.

joevt said:
I have done Thunderbolt Target Display Mode from a Mac mini 2018 to a 2013 iMac in macOS 12 Monterey.
Click to expand...
Do you mean you 2013 iMac has Monterey on it? I didn't think Target Display Mode worked with newer OS versions on the target display Mac.
 
J

joevt

Contributor
Jun 21, 2012
6,880
4,174
Juicy Box said:
Do you mean you 2013 iMac has Monterey on it? I didn't think Target Display Mode worked with newer OS versions on the target display Mac.
Click to expand...
Yes. Both the Mac mini 2018 and the iMac 2013 are running Monterey. The iMac 2013 is using OCLP to boot Monterey. Connect them with Thunderbolt (with or without a Thunderbolt 3 dock between them), check that each Mac can see each other in the Thunderbolt tab of System Information.app, then press Command-F2 on the iMac keyboard to cause it to switch its display source from its GPU to the GPU of the Mac mini.

The iMac is still usable if it has a second display, or if you use screen sharing to the iMac. Press Command-F2 once or twice to restore its display to itself.
 
W

Wingsley

macrumors 6502
Original poster
Mar 20, 2014
297
37
joevt said:
Yes. Both the Mac mini 2018 and the iMac 2013 are running Monterey. The iMac 2013 is using OCLP to boot Monterey. Connect them with Thunderbolt (with or without a Thunderbolt 3 dock between them), check that each Mac can see each other in the Thunderbolt tab of System Information.app, then press Command-F2 on the iMac keyboard to cause it to switch its display source from its GPU to the GPU of the Mac mini.

The iMac is still usable if it has a second display, or if you use screen sharing to the iMac. Press Command-F2 once or twice to restore its display to itself.
Click to expand...

The 2013 iMac cannot run MacOS Big Sur or newer. So, that vintage iMac will never run Monterey.
 
Juicy Box

Juicy Box

macrumors 604
Sep 23, 2014
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Wingsley said:
The 2013 iMac cannot run MacOS Big Sur or newer.
Click to expand...
Well, not officially.

There is always a way to do things, unofficially.

I have been putting unsupported OS versions on my older Macs for years.

I daily use a Mac Pro 1,1 which cannot run beyond 10.7 Lion, but it is currently running 10.11 El Capitan, and runs it very well.
 
W

Wingsley

macrumors 6502
Original poster
Mar 20, 2014
297
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I have decided to abandon the issue of using the old iMac in "target display mode".

I remembered last night that I have another ace-in-the-hole... Back in 2007, my G4 "igloo" iMac started having problems with its built-in 17-inch LCD display. It would flicker and ultimately fail. A friend recommended that I buy an Acer AL1716W A 17-inch external LCD display and a VGA-to-Apple Display Adaptor so the Acer could be driven by the iMac. Guess what? I not only still have the old "igloo" iMac (it runs some old 1990s-vintage software I use, once-in-a-blue-Moon), but I still have the Acer display. So if I need a monitor to connect to a new Apple Silicon computer, voila!

Now I have to find a way to drive a 2007-vintage VGA monitor in 2022...

New thread being started on that one!

Thanks, everyone for participating here!

Closing this one out.
 
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