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Recently (less than one year ago) i bought an iMac 21,5". Now i would like to use it as secondary monitor for my laptop. (My laptop runs Windows 7).

Is it possible? (I found conflicting opinions on the web, even on the Apple forum).

What type of cable do I need? (I will appreciate also a link to the product on some online store: amazon, ebay etc.)

Thank you in advance.

UPDATE:

I tried air display... i'm not satisfied at all...

typical scenario: browser window on the main Windows laptop, dev tools/firebug on the secondary iMac screen. The mouse goes fast between the 2 screens (GOOD), but when i changed the selected tab nothing happens. I had to drag the dev tools window to the main screen to get an update of the selected tab. My test is ended here.

I'm still waiting for other answers.

I will prefer an answer that suggest me what kind of cable i've to buy, and where i can find it on the web.

share|improve this question
    
I did more research on this and found out that you could try a DVI to Mini DisplayPort Converter (though opinions diverge on whether it will work with a Thunderbolt display). See my answer below for details. –  jaume Apr 4 '13 at 8:50
    
@jaume I'm really grateful for the help you're giving me –  Bruno Apr 4 '13 at 9:30
    
As far as i have come : my laptop is a lenovo with a so called display port (looks a bit like hdmi but isn't) and a 2013 imac: no chance to have the imac as a monitor. 2012 imac would work though, just need to have the cable. –  user51703 Jun 21 '13 at 18:59
    
Can you share where you got that information? What's the difference between years that breaks it? Have you successfully used a 2012 iMac with your Lenovo? –  ruffin Dec 7 '13 at 17:54
    
Looks like it says about as much here. –  ruffin Dec 7 '13 at 18:02

1 Answer 1

up vote 8 down vote accepted

All Thunderbolt-equipped iMacs, like your iMac (Mid 2011), support Target Display mode:

Target Display Mode lets you use your iMac as the external display for another, “primary” computer.

Thunderbolt-only solution

If you happen to own a laptop with a Thunderbolt port follow these simple steps to extend your display (Thunderbolt to Thunderbolt cable required) (from KB PH4469):

  1. Connect the Thunderbolt cable to the Thunderbolt ports on each computer.
  2. Make sure the iMac and the primary computer are turned on and awake.
  3. Press F2 on the keyboard of the iMac.

(As a side note: Older iMacs with Mini DisplayPort also support Target Display Mode. The steps to configure and enable Target Display mode are very similar.).

A comment on DVI to Thunderbolt adaptors

You can't use Mini DisplayPort to DVI or VGA adaptors:

enter image description here

to connect a computer with a DVI/VGA port to a Thunderbolt display (from this thread):

I can confirm that Mini DisplayPort to DVI converter works ONLY from a Mini DisplayPort computer port to a DVI display. The reverse direction is not supported by those converters,

There is some hope, though, as the post goes on to say:

but there are other much more expensive ones that will convert DVI computer ports to Mini DisplayPort display.

The poster is probably refering to a product mentioned earlier in the thread: the Kanex C247D Single-Link DVI to Mini DisplayPort Converter, advertised like this:

Connect a (...) LED Cinema Display to your DVI-equipped MacBook Pro, Mac Mini, or PC with this (...) Kanex solution.

However, opinions diverge on whether it will work with a Thunderbolt display at all:

  • I am sure that Kanex don't do anything that will help you no matter how expensive it may be.

  • As far as I am aware, and I have done a lot of reading about this, you can connect an older display to the new Thunderbolt port of a new MAC but you CANNOT connect the Thunderbolt display to anything other than a MAC with a Thunderbolt port. The Kanex thing works from a Thunderbolt port into an older display, DVI or whatever but you cannot convert MAC DVI into Thunderbolt......I think

I've noticed that the LED Cinema Display is listed as a Mini DisplayPort display (from http://support.apple.com/kb/SP502):

enter image description here

so the adaptor may indeed only work with Mini DisplayPort displays, not with Thunderbolt displays, and as far as I can tell, your iMac will act like a Thunderbolt display.

It's up to you to try it, although $129.90 (as of this writing) is a steep price to pay for the Kanex adaptor just to test it.

Software-based solution

If the solutions described above aren't feasible or cost-effective, you can use several software solutions. One is Air Display:

Use your iPad, iPhone, Android, Mac or Windows PC as a second (or third) monitor with no messy cables or wires

enter image description here

There is a free trial version here.

Note: Windows 7 Starter edition is not supported.

share|improve this answer
    
Currently, I cannot verify... but i'm pretty sure that my personal laptop run the "home edition" of windows 7... So this solution does not fit my need... However, thank you for your answer. –  Bruno Apr 3 '13 at 10:06
    
The Windows 7 Home edition (both 32-bit and 64-bit) is supported by Air Display, the restriction only applies to the Starter edition. See en.wikipedia.org/wiki/Windows_7_editions#Main_editions for more information on the Windows 7 main editions. –  jaume Apr 3 '13 at 10:14
    
My dyslexia strikes back again... thank you :) I will give a try –  Bruno Apr 3 '13 at 10:16
1  
@jaume I went to add a short explanation of target mode video to explain the "cables needed" portion of the question and found it's not a short edit. Feel free to reorder things so AirDisplay is up top or reject my edit entirely if you're not comfortable collaborating on one answer covering both hardware and software. –  bmike Apr 3 '13 at 12:26
1  
@bmike Thanks, this makes the answer definitely more useful. As you can see, I modified your edit to highlight the steps relevant to the OP's hardware while mentioning the other information as a side note. –  jaume Apr 3 '13 at 13:41

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