11 Replies Latest reply: Jan 17, 2013 12:55 AM by Stefano Stramigioli
Stefano Stramigioli Level 1 (10 points)

I have a Imac 27 Mid 2010 and after reading the article I bought a ridiculously expensive Thunderbolt cable to use my MAC as a monitor, but it does not work!! The cable is fine because on another iMAC it does work, by my IMac 27 is Mid 2010 and this article says it should work. Why isn't apple realising a firmware update hiwch makes this possible? I stept over from Microsoft to Apple because I did not like the way they were doing, but Apple is really becoming more and more like Microsoft...

iMac, Mac OS X (10.7.5), Mid 2010
  • babowa Level 7 (29,080 points)

    I'm sorry, but I could find absolutely no mention of Thunderbolt in the article you are referencing. Mid 2010 iMacs do not have a Thunderbolt port - I know because I have one. Here are the specs:




    and these are the ports on the 2010 iMacs:


    Screen Shot 2013-01-09 at 11.34.32 PM.png

  • Stefano Stramigioli Level 1 (10 points)

    Sure, but the issue is that the IMAC has a video port (same socket as thunderbold) and I have a new Retina display with 750 SSD. I want to use the IMac as a monitor (it has the connector for that). The article I referenced sais it should be possible, but it does not work. Why? I do not want to use "thunderbold capabilities" of the IMac, but just its video and it has an input for that. On the other hand, the brand new Retina MacBook pro has a thunderbold which I use regularly with the video adapter for external screens. So, if I buy a Samsung monitor it would work, but I cannot get it to work with a top of the line IMac of Mid 2010 which has an input video? Difficult to understand for me.

  • LousyFool Level 4 (2,645 points)

    Stefano Stramigioli wrote:


    Difficult to understand for me.

    Let's try to make it simple then:

    • Forget about Thunderbolt, at least for what you're up to here, except for the last point here below.
    • Do as the article says:

    - Target Display mode requires a Mini DisplayPort to Mini DisplayPort cable...

    - Connect a male-to-male Mini DisplayPort cable to the Mini DisplayPort on each computer.

    • Do not "read" words in the article which are not written there.
    • Return your Thunderbolt cable and, again, get a Mini-DP->Mini-DP cable. Yes, it will work.
  • Stefano Stramigioli Level 1 (10 points)

    My comment "Difficult to understand" was sarcastic: I have enough technical background to understand all this, but it seems to me a really bad choice that there is another cable Mini DisplayPort-MiniDisplay port which has the same plugs and a different wiring: the only cable which I could find on the store which has male-male mini-video=thunderbold connector is the one I am using and it does not work.


    I will look for a Mini-DP->Mini-DP cable if available then, but once again it is at least missleading that such male-male cable with the same socket have different wiring. In RJ45 that is the case for cross cables, but the MAC can handle both by electronic switching I bilieve and it is surprising something like this happens here with thunerbold/mini DV sockel like cables.


    Anyhow, thanks for the FB.

  • Stefano Stramigioli Level 1 (10 points)

    DV-> ment Mini Video of course.. DV is something else

  • LousyFool Level 4 (2,645 points)

    Okay, two more pieces of info to add to your technical background:


    Thunderbolt (TB) is downwards-compatible with Mini-DP, which is the reason for the connectors being the same. Being able to plug a Mini-DP screen into a TB jack and have it working is a benefit; hence, using the same connectors is a feature, not a flaw.


    Then, TB is a newer technology than Mini-DP, and yes, the cable is different. You will actually see optical TB cables in the future - don't be surprised if TB cables, now or in the future, do not support a Mini-DP->Mini-DP connection.


    Your RJ45 analogy is incorrect as well: you will have to agree that there are different cables in between RJ45 connectors: Cat-5, Cat-5e, Cat-7 etc, ISDN, to name a few. Depending on application some work and some don't. Wrong cable = no or reduced function.


    'Nuff said.

  • Stefano Stramigioli Level 1 (10 points)

    Have you some links where I can then buy such a Mini-Dp -Mini-DP cable or in a worst case a wiring scheme so that I can make one myself? I did not find it in the shop and also I do not seem to find it in the Apple Store on line. You can find plenty Mini-DP to HDMI cables. Is the wiring such that it would work by using an HDMI cable and 2 Mini-DP to HDMI adapters? I would expect not being ment as "an output". Thanks in advance for the answer.

  • Stefano Stramigioli Level 1 (10 points)

    Thanks, but if you read in the specs of some of those cables (in dutch) they say: "This cable can ALSO be used as a thunderbold cable between thunderbold devices" which would then imply it has the same wiring. Let's close the discussion and I will see what to do. ThanX

  • LousyFool Level 4 (2,645 points)

    Yup, a Cat-5 cable can also be used for ISDN... if all pins are used...



  • Stefano Stramigioli Level 1 (10 points)

    Dear LousyFool, thanks a lot! I got the Mini-DP to Mini-DP cable and voitla! IT works! I will look for wiring specs because this really puzzled me, but you were as expected right. Thanx a lot!