Previous 1 11 12 13 14 15 Next 214 Replies Latest reply: May 11, 2010 8:09 PM by Knut Schartmann Go to original post
  • Rod Hagen Level 7 Level 7 (31,985 points)
    From what I can see there, macpro8, the first two adaptors you list are MDP to DVI. Neither of them provide support for the analogue signal , and neither of them, accordingly will work together with a DVI to composite /S_Video adaptor to provide a composite signal.

    Not sure which of the ones in the last link you were thinking of, but none of them that I can see there will work to achieve composite or S-Video without the use of an additional active digital to analogue signal conversion box.

    You will find a useful illustrated guide to a setup that WILL work at http://createdigitalmotion.com/2008/10/macbook-pc-notebook-with-no-analog-output -tested-solutions/



    Cheers

    Rod
  • Phlegon Level 1 Level 1 (0 points)
    It's amazing how much information in this thread has been forgotten, apparently because people aren't reading the beginning. The questions you're all asking were asked and answered almost a year and a half ago (although not the question as to why Apple hasn't created a solution for this).

    Go back and look at this message in this same thread: http://discussions.apple.com/message.jspa?messageID=8361557#8361557

    Hopefully that helps! I think I'm finally going to order one myself.

    Update: Just noticed that the article Rod linked to above actually references the post I linked to in this very thread.

    Message was edited by: Phlegon
  • Davidros Level 1 Level 1 (10 points)
    Yes, that is true. If only it were possible to make that a sticky at the start of every page in this thread. That PC to Video EZ box (link above) and subsequent, ludicrous mess of cables is your only semi-practical MBP solution to composite.

    However, I still don't understand why it was possible to make mini displayport to VGA but not to composite rca. (Isn't VGA analog?)

    If someone would explain that part to me, it would greatly satisfy my curiosity and I'd be thankful!
  • kompot Level 1 Level 1 (20 points)
    I tried your method. Did everything as you said. Removed pin 12 from VGA cable. But nothing happens except my Macbook screen goes blue for sec with NO second display found. Neither I get signal on TV.
    I didnt shorten pins on S-video part cause I connect throw yellow RCA cable in this way:
    Macbook (Pro) -> MiniDP to VGA -> VGA to S-Video/RCA -> RCA to TV.

    Is this ok or I need to go over S-video. If so which two pins I need to short then?

    And did you made it work in OSX or WIN?
  • Knut Schartmann Level 1 Level 1 (75 points)
    I just got on board in this topic but I did actually read every post starting at the beginning - took a while.

    What I don't fully understand is the technical aspect - nobody seems to have discussed or looked into this and I would love to hear some comments from the people who know.
    Here is my take:
    Composite video, component video, S-Video and VGA are all analogue signals but that's all they have in common.
    Each one of these is technically very different in the way the information is transmitted - it's not just different pin-outs of the same signal.
    DVI and DisplayPort are digital signals also very different - neither is a subset of the other.
    Mini-DVI is just a remapping of the DVI to a smaller connector, but the signals are the same as DVI.

    Now for the original DVI spec besides the digital DVI signals the spec and the connector also accommodates the VGA signals, the three colours, horizontal and vertical synch and the grounds.
    DVI ports that bring out both the DVI signals and VGA signals are called integrated (or I); then there are DVI ports for digital only or analogue only and those are missing the pin outs that are not required.

    So.......making a DVI to VGA adapter is just a pure cable with a DVI connector on one end, a VGA connector on the other end and the proper mapping of the wires between them - simple enough.
    Mini DVI the same thing.
    Both of these of course assume that the Mini itself generates both DVI digital and VGA analogue signals and outputs them on a DVI-I port.

    Where I'm having trouble is with the following:

    a. The older DVI-Composite/S-Video adapter.
    ...Since there is no composite signal or S-Video signal defined for any of the pins in DVI (like there is for VGA), did the Apple adapter actually have active circuitry in it that converted either DVI or VGA (which were both present) to composite and S-Video?
    I imagine it would be VGA to composite/S-Video converssion, but I don't know.
    Anyone have more insight here?
    and what puzzles me even more is the

    b. DisplayPort to VGA adapter - there are no VGA signals defined in the DisplayPort spec, at least none that I see.
    So how does that conversion actually take place? That has to be some active circuit as well not just a straight wire feed through like the DVI-to-VGA adapter.
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