[Pc_Support] Wikipedia: DVI Connector and Specification

[Bryan J. Smith]

For more on DVI, see the excellent Wikipedia page, namely the
Connector section:
  http://en.wikipedia.org/wiki/DVI#Connector

Most video cards today are Single Link DVI-I, meaning they can send
either digital or analog signal.  The analog "RGB" is located in the
"plus" portion.

Most LCD displays are Single Link DVI-D, meaning they can only accept
a digital signal.  But the majority also have a mini-DB15 (VGA) in,
which can handle analog.

Again, a few video cards lack the analog RAMDAC for analog or, more
likely, lack dual-RAMDACs, so their DVI connector is only a DVI-D.
E.g., again, the GeForce 61xx series of GPUs are commonly implemented
with only a single RAMDAC, so if there is both a mini-DB15 (VGA) and
24-pin (DVI), the latter is only a DVI-D and not a DVI-I (as the
RAMDAC is only connected to the former).

Also note the Specification section:
  http://en.wikipedia.org/wiki/DVI#Specifications

It lays out the maximum data transfer rate (DTR) of single link
(3.7Gbps) and dual link (7.4Gbps).  I believe the physical, analog
maximum is around 6GHz given the gage of the wire, hence these
limitations.