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laurie27

macrumors newbie
Original poster
Mar 26, 2020
3
0
Hi,

Newbie here...

I'm trying to use my older iMac (21.5-inch, Late 2009) as a second monitor for my MBP (Retina, 15-inch, Mid 2015.) I've read about Trigger Display Mode (TDM) which I don't believe is supported on my iMac. Is it possible to use the iMac as a second monitor? If not, what about as simply an external display?

Thank you!

Laurie
 

jcjost

macrumors newbie
Mar 26, 2020
6
1
Hi,

Newbie here...

I'm trying to use my older iMac (21.5-inch, Late 2009) as a second monitor for my MBP (Retina, 15-inch, Mid 2015.) I've read about Trigger Display Mode (TDM) which I don't believe is supported on my iMac. Is it possible to use the iMac as a second monitor? If not, what about as simply an external display?

Thank you!

Laurie
I use Luna Display in order to use my 24" iMac (late 2008?) as a second/extended monitor with my 27" iMac (late 2012). It works quite well and should work with your MBP. See https://lunadisplay.com --John
 
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laurie27

macrumors newbie
Original poster
Mar 26, 2020
3
0
I use Luna Display in order to use my 24" iMac (late 2008?) as a second/extended monitor with my 27" iMac (late 2012). It works quite well and should work with your MBP. See https://lunadisplay.com --John
Hi John,

This looks like a viable option! I'm still wondering if there's a cabled solution as I'd prefer not to deal with multiple app versions on the main and target systems. How is the company wrt updates, etc?

Thanks!

Laurie
 

jcjost

macrumors newbie
Mar 26, 2020
6
1
The Luna adapter (which you have to purchase) is plugged into my main display. My main display is connected by ethernet to the router. My secondary display is also connected by ethernet to the router. (I don't use Luna's wireless option.) Each display must have the the Luna app installed -- you can't avoid that. I don't know about updates to the apps, I've only had the Luna for a few months. It's a bit slow to start, but overall I'm quite happy with it. --John
 

laurie27

macrumors newbie
Original poster
Mar 26, 2020
3
0
The Luna adapter (which you have to purchase) is plugged into my main display. My main display is connected by ethernet to the router. My secondary display is also connected by ethernet to the router. (I don't use Luna's wireless option.) Each display must have the the Luna app installed -- you can't avoid that. I don't know about updates to the apps, I've only had the Luna for a few months. It's a bit slow to start, but overall I'm quite happy with it. --John
Thank you!
 

Lixr24

macrumors newbie
Aug 21, 2021
2
0
Hi,

Newbie here...

I'm trying to use my older iMac (21.5-inch, Late 2009) as a second monitor for my MBP (Retina, 15-inch, Mid 2015.) I've read about Trigger Display Mode (TDM) which I don't believe is supported on my iMac. Is it possible to use the iMac as a second monitor? If not, what about as simply an external display?

Thank you!

Laurie
 

Lixr24

macrumors newbie
Aug 21, 2021
2
0
Hi Laurie,

By any chance were you able to figure out how to connect iMac (21.5-inch, Late 2009) as a second monitor? Im still having issues connecting my iMac (21.5-inch, Late 2009) as a second monitor.
 

natj910

macrumors newbie
Aug 2, 2021
10
3
Hi Laurie,

By any chance were you able to figure out how to connect iMac (21.5-inch, Late 2009) as a second monitor? Im still having issues connecting my iMac (21.5-inch, Late 2009) as a second monitor.
Target Display Mode doesn't work on 21.5in iMacs, only 27in iMacs.

In case anyone comes along here given it's an old thread, I'm pretty sure a mini displayport to mini displayport cable will suffice for this connection. I'm yet to try it from my 2015 MBP to my 2010 27in iMac but will buy a cable to give it a go eventually.
 

ADGrant

macrumors 65816
Mar 26, 2018
1,320
774
Target Display Mode doesn't work on 21.5in iMacs, only 27in iMacs.

In case anyone comes along here given it's an old thread, I'm pretty sure a mini displayport to mini displayport cable will suffice for this connection. I'm yet to try it from my 2015 MBP to my 2010 27in iMac but will buy a cable to give it a go eventually.
Target Display Mode doesn't work on 27" iMacs either if they have the 5k retina screen. Should work on your 2010 though.
 

natj910

macrumors newbie
Aug 2, 2021
10
3
Target Display Mode doesn't work on 27" iMacs either if they have the 5k retina screen. Should work on your 2010 though.
Well aware, but that's kind of redundant anyway considering that it only works on machines up to Mid 2014, the 5k retina 27in iMacs were all Late 2014 or later.
 
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