Using iMac As Monitor Requires Very Specific Cable

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To use the new 27-inch iMac as an external monitor requires a very specific cable to work: a Mini DisplayPort to Mini DisplayPort cable, to be exact.

It does not work with a HDMI cable or a DVI cable, even when they are strung between a pair of Apple-branded Mini DisplayPort adapters.

There seems to be a lot of confusion about the issue on the web and even at Apple’s retail stores.

The staff at the main San Francisco Apple store were confused about the cables needed to use the iMac as an external monitor for a compatible MacBook Pro. The iMac works only with devices that output video through DisplayPort, which the MacBook does.

To use the new iMac as a monitor, it must enter “target display mode,” which appears to happen automatically when the correct DisplayPort cable is plugged in.

There appears to be only one cable on the market capable of connecting compatible devices to the new iMac: Belkin’s Mini DisplayPort to Mini DisplayPort cable, which is available from Apple’s retail stores for $29.99.

The store didn’t have any in stock, so the staff happily sold me a pair of Mini DisplayPort to DVI Adapters ($29 a pop) — and told me to string them together with a standard DVI cable.

I had to go to another store to find a DVI cable to connect them (another $20). At this store, I found a pair of DisplayPort to HDMI dongles, so I picked them up (another $15 each) and a $12 HDMI cable to connect them.

Neither of these MacGyver solutions worked.

I’ll try to pick up one of the Belkin cables tomorrow and will post the results here.

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I tried to use a new 27-inch iMac as an external display for a compatible MacBook. I connected them with a HDMI cable connected to two Mini DisplayPort to HDMI adapters. It didn't work.

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Neither would a DVI cable strung between two Mini DisplayPort to DVI Adapters.

Related
  • Pavel

    I’m trying to hook up my asus laptop to my imac using an hdmi cable and a generic mini display to hdmi; with 0 luck…. FML

  • Lingraham

    I am trying to use my MacBook laptop computer as a screen for my desktop PC. Can I do this with the special MAC adapter cord that goes from the PC to the laptop? I don’t want to wreck anything. Thanks

  • Joel Nichols

    @Lingraham: That won’t work. This only works with the 27″ iMac.

  • fletc3her

    In my experience it doesn’t work even if you have the right cables. I have the Belkin cable and have tried several different MacBook Pros with every configuration of display settings I could think of. Is there any confirmation this works at all?

  • kisiel

    The adapters pictured above are unidirectional, i.e. from mDP to HDMI/VGA/DVI only. iMac 27 will work only a mDP output singal. So unless the video card of your device outputs mDP you will need a converter/scaler to use your iMac 27 as a monitor. This is a rather expensive set up as a these units sell around $200 plus the mDP to mDP cable.

  • Robert Stothard

    I found the simplest solution was to just remote desktop to the PC.  I have plugged an Ethernet cable direct from iMac to Laptop no need even for a switch.  Ok, I don’t get to use both the laptop and the imac screen but I do get to use this amazing screen for my laptop.

  • Leyi Zhang

    Any result updated?

  • Mohd Fikree Mohd Fauzi

    looks like a good idea, but is it work, what software ure using, yesterday i build a new pc, then try to connect to iMac as Display… but can’t working… 
    (iMac late 2009, c2d extreme 3.06, hd3650, 6Gb RAM, 1TB) (PC – phenom am3 X6, 8Gb, 1TB, fx 3450)

  • Andreas Straub

    You have to put the iMac in Target mode (reboot and push the “T” key) and you have to use a displayport connection.

  • watzlav

    Does this also work with the 21.5” Model?

  • watzlav

    Does this also work with the 21.5” Model?

  • watzlav

    http://support.apple.com/kb/ht… – apparently Apple says it does.

  • Vinnie Venkov

    I am looking cable or product for monitoring iPhone4 on my iMac.Somebody knows the  solution…? 

  • Erich

    This is a similar problem to one of the posted Apple support forums relative to using a TV as a monitor.  The forum I found started in 2009, and 22 pages later, in August, 2011, there seems to be no valid answer!  Apple clearly is not a service-oriented company, and it’s products do not perform as advertised, at least in this regard.
    It’s interesting to note that my old, should-have-been-retired-long-ago G4 laptop works perfectly using my TV as a monitor with a cheap DVI to HDMI cable.  My 2010 iMac cannot be made to work in the same manner.  It’s mini displayport to DVI to HDMI cable’s signal can’t be recognized my the TV.

  • Guest

    I have used my TV as a display for my MacbookPro.  I was taught this in an Apple store.  I used the miniport to HDMI cable to connect the devices.  Then in the preferences on the Macbook, I went to displays.  It shows an arrangement tab. When I opened that tab, it shows two screens side by side.  I was taught to select the thin white rectangle (the menu bar) and drag it onto the larger screen (the TV).  The cursor can move between the two screens, but you have to figure out which side it comes in on.  If I take this system to hotels, etc., I will sometime have to reset the sound output in preferences as well.  
    You can also check “mirror” and you will see the same output on both devices.

  • Erich

    Yeah, thanks anyway, but many, many of us get nothing showing in the display preferences.  If you’ve not nothing showing, your computer is not recognizing the TV (and vice versa).  It’s a bit hard to believe, but it must be so, that iMacs simply can’t use TVs as a display monitor.  I’ll repeat myself:  My old G4 Laptop works with the TV as a monitor, buy my new iMac doesn’t.

  • Ant

    I think the main issue here is that it simply won’t work with the older style macbook;s (2008 or earlier) that only have DVI out. Display port has connectivity to signal the iMac to become a monitor… those signals arn’t passed through DVI out. It’s a guess, but i’ll bet money on it.

  • Pepilurose

    Thank YOU so much!!!!!

  • metalim

    IMO MiniDP-to-HDMI and MiniDP-to-DVI adapters allow host only on MiniDP end.
    If that’s the case, then putting couple of them on both ends of another cable would be useless.

  • Mangesh Gondhalekar

    Have you tried any of these solutions: 
    http://avatron.com/apps/air-di… or 
    http://www.screenrecycler.com/… 

  • Johnny Wu

    Hi Leander, did the Belkin finally work?  You never posted the result.

  • Snapperou812 None

    Using a iMac with the right cable that only has MiniDP ends and the output of the PC video has a miniDP it takes over the iMac and you now have a very expensive monitor for your pc.

  • Andrew Frazer

    Bought the cable, it works without trouble. Thanks saved me a $1000 buying a new display!

  • jamestracy

    Hi i need help , yeah , i have Mac pro desktop 2008 and iMac 2001 , and I’m trying to plug the mac pro in to my iMac as a display mode , and my Mac pro has just 2 connections DVI only, there is a possibility to do that ? i want to plug my Mac pro as the Main computer and iMac pro 2011 as display mode . there is a cable for that , going to DVI and converter do mini display mode ? thank you for help .

About the author

Leander KahneyLeander Kahney is the editor and publisher of Cult of Mac. He is the NYT bestselling author of Jony Ive: The Genius Behind Apple's Greatest Products; Inside Steve’s Brain; Cult of Mac; and Cult of iPod. Leander has written for Wired, MacWeek, Scientific American, and The Guardian in London. Follow Leander on Twitter @lkahney and Facebook.

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