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Re: How to know if DVI connection is digital or analogue?



On Mon, Mar 08, 2010 at 10:49:25PM +0200, Dotan Cohen wrote:
> > Check this pic:
> > http://www.playtool.com/pages/dvicompat/sldldvi.jpg
> >
> 
> I had no idea it was such a mess! Three different types of DVI?!? One
> for D, one for V, one for I?!?

As you can see from the pictures, the pinout variations¹ allow different
subsets of the pins to be used.  Typically the female end on your
graphics card will be DVI-I and support all options, while the cable from
the display will have just the subset of the pins it needs.


For example, if you connect a digital monitor to a DVI-I port it *can't*
use analogue signalling: it's physically missing the C1-C4 R/G/B/HSync
lines.  Typically these would only be found in a DVI->VGA converter or
cable.  Just checked my monitors' cables and they are all DVI-D; if it's
an LCD, it probably won't even have the ability to do the analogue to
digital conversion, even if the connector didn't physically prevent it.

There may be weird monitors out there that accept both digital and
analogue inputs over DVI, but I've never seen one.  If you are
suffering from such a situation, using a DVI-D cable would prevent any
use of analogue signalling.

The only other variations are dual link (just an extra 6 pins), and
DVI-A for analogue only (I've never ever seen this one, and this is
just the C1-C4 pins and 3 data pins removed).


Regards,
Roger

¹ http://www.interfacebus.com/Design_Connector_Digital_Visual_Interface_DVI_Bus.html

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