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Apple’s new laptops employ Mini-DisplayPort

Posted by bitguru on October 14, 2008

standard USB port next to Mini-DisplayPort

Until today, Apple’s three laptop lines used different display connectors. The MacBook used mini-DVI, the MacBook Air used micro-DVI, and the MacBook Pro used vanilla DVI. I thought Apple might standardize on a single display connector, perhaps micro-DVI.

I was partially correct. Today’s updated versions of the MacBook, MacBook Air, and MacBook Pro do all use the same display connector, but it’s mini-DisplayPort, not micro-DVI.

Apple needed another laptop display connector like a moose needs a hat rack, but mini-DisplayPort does have some advantages. For one, the connector is small—about 60% the size of a standard USB-A connector. (See comparison image, above.) It has a 1 Mbps bi-directional (half-duplex) auxiliary channel that could be used to handle webcam or other peripheral data. It can also drive resolutions above 1920×1200, which dual-link DVI can handle but single-link DVI variants can not. Perhaps the connector will mate with the socket more securely than mini-DVI does, but this is yet to be determined. (Latching is a feature of standard DisplayPort connectors, but so far as I can tell Apple created mini-DisplayPort on its own. It is unclear if mini-DisplayPort connectors latch. [update: They don't.])

The downside? Mini-DisplayPort is presumably signal-compatible with standard DisplayPort, which “is the future” but hasn’t really caught on yet. This will likely be a win in the long term, but it’s not signal-compatible with DVI or HMDI (nor VGA, for that matter). DisplayPort implementations are permitted to pass DVI-compatible signals through the connector, and presumably this is what Apple has done, at least for single-link DVI.

Apple’s $29 Mini DisplayPort to DVI Adapter supports single-link DVI. To exceed 1920×1200 requires the Mini DisplayPort to Dual-Link DVI Adapter, priced at a whopping $99. Presumably the dual-link adapter has circuitry that actually converts the DisplayPort signals, which is why it requires USB power. (There is also a $29 Mini DisplayPort to VGA Adapter.)

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8 Responses to “Apple’s new laptops employ Mini-DisplayPort”

  1. Reid said

    Here’s a question I haven’t seen answered anywhere yet: Is it possible to get an adapter that will let some of the millions of people out there with Mini-DVI ports use a display that only has a Mini-DisplayPort cable? More to the point, can my 3-month old MacBook ever connect to the new LED Cinema Display?

    [answer: most likely not (see 5th paragraph) -ed.]

  2. There are a lot of pretty compelling reasons to use
    DisplayPort – especially in laptops.
    There is a 3 part series of articles on DisplayPort that cover the advantages of cost, performance & design, and future capabilities.

    1 Display Port avoids the $10k/year license fee of HDMI

    2 Display Port direct-drive technology eliminates the cost for additional circuitry in computer displays

    3 Display Port uses direct-drive technology, enabling ultra-thin displays and a setting a common standard for laptop and stand-alone displays

    4 Display Port can drive 30-bit (billions) of colors at high-resolutions and high refresh rates

    5 Display Port uses smaller, latching connectors and can handle longer cables
    [But mini-DisplayPort connectors do not latch. -ed]

    6 Display Port is compatible with 45 nm chips that everyone wants to build (DVI and HDMI draw too much power)

    7 Display Port enables things like webcams, touch-screens, and USB all over the same cable – so multi-touch can be built into the screen directly.

    8 Display Port can handle multiple video and data channels over the same wire – so think things like picture in picture

  3. Ted said

    Just pondering, does this implementation allow 2 adapters to be used together, i.e. mini DisplayPort-DVI adapter, DVI-VGA adapter?

    [I can't say for sure, but I doubt it. Apple's existing mini-DVI port can't even do that, and DisplayPort signals are different to begin with. There is some further information here. -ed.]

  4. I saw Apple’s new laptops in person today. I was able to [...]

  5. Peter said

    I just phoned the number at VESA and Displayport.org. The director’s assistant told me that at this time they know of no Mini displayport to standard displayport cable or adapter. She said to contact Apple. I have a new macbook pro and Dell 2408 monitor with a displayport. But of course Apple’s mini displayport port is non-standard. Hopefully somebody will soon come up with a single cable or a small adaptor. In the meantime I’m using Apple’s mini display port to DVI adaptor. That works fine, but I’d like to take advantage of the displayport technology. I guess this will be an ongoing topic. Peter
    VESA contact info:
    Bill Lempesis
    Executive Director
    860 Hillview Ct., Suite 150
    Milpitas, CA 95035
    T: 408.957.9270
    F: 408.957.9277

  6. [...] You’ll get quite a few of Apple’s own product pages, as would be expected. But only a few blogs are calling Apple [...]

  7. [...] I thought we’d see third-party miniDisplayPort-to-DisplayPort adapters by now, but I have yet to find one. My unamed source says that Apple has contributed the mini-DisplayPort connector specification to VESA for possible inclusion in version 1.2 of the DisplayPort standard. If so, cheap third-party mini-DP adapters should be around the corner. [...]

  8. [...] Apple released new Mini models this morning. The processors are about the same as before—no complaints there—but other components have moved from five-year-old technology to parity with the modern MacBook:
    * Nvidia GeForce 9400M graphics (from Intel GMA 950)
    * mini-DVI and mini-DisplayPort with dual-display support (from one full-size DVI port)
    * 4GB RAM ceiling (from 2GB)
    [...]

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