It’s been more than a month since Apple introduced the Mini-DisplayPort connector on its new line of laptops. Here are some thoughts.
I had presumed that Mini-DisplayPort was signal compatible with standard DisplayPort, with the same 20 pins (but in a different order), but there was no corroboration. Well, my unnamed source (how mysterious!) confirms that this is the case.
[update: Shortly after I published this entry, further validation came in the form of a mini-DisplayPort licensing page on Apple’s web site. It supplies a PDF download for mini-DisplayPort connector dimensions and pinouts.]
I mentioned that Apple was continuing to sell its 23″ Cinema Display (with DVI) an addition to its new mini-DisplayPort-only 24″ Cinema Display. However Apple has since discontinued the 23″ model, leaving it without a mid-range display that can be connected to any existing Apple desktop machine. This indicates to me that Apple soon plans to release new versions of the MacPro, iMac, and MacMini that will have Mini-DisplayPort ports. (It still sells 20″ and 30″ displays that support DVI, but for how much longer?)
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. (Component manufacturing giant Molex has apparently been working on making the connectors available.) This would allow Macs with mini-DisplayPort to drive standard DisplayPort monitors, and laptops and video cards with standard DisplayPort to drive Apple’s LED-backlit Cinema Displays.
- It may be possible to create an unwieldy miniDP-to-DP adapter today:
- start with an Apple miniDP-to-DVI adapter
- connect it to a standard M/M DVI cable, the shorter the better
- connect that to a third-party DisplayPort-to-DVI adapter
- finally put an F/F DisplayPort coupler on the end
The idea is to convey the native DisplayPort signals (not DVI signals) through the conductors of the DVI cable. This presumes that the two adapters have compatible pinouts and that they have enough conductors. (The pinout of that DisplayPort-to-DVI adapter shows 17 conductors, omitting only pins 13/14/16. DisplayPort cables are supposed to leave out 13 and 14, but not 16. It might be ok to leave out 16, though, since it would only be used by the auxiliary channel.) A bigger presumption is that the F/F DisplayPort coupler doesn’t cross conductors 1-12, which unfortunately it would have to do if it’s intended to allow two coupled standard DisplayPort cables to behave like a longer standard cable. My guess is that this crazy adapter wouldn’t work, but if anyone actually tries it please let me know the result.
Many have run into DRM problems viewing media through the mini-DisplayPort connector—even standard-definition stuff that shouldn’t be affected by HDCP. This is yet another case of Digital Rights Management causing problems for legitimate users. It’s getting old. Supposedly, a QuickTime 7.5.7 update addresses the issue.