Two Varieties of DVI Connectors

• Single-link DVI employs a single 165 MHz transmitter that supports resolutions up to 1920 × 1200 at 60 Hz.

• Dual-link DVI adds six additional pins (located in the center of the connector) for a second transmitter increasing the bandwidth and supporting resolutions up to 2560 × 1600 at 60 Hz.

Some DVI connectors also have pins that pass an analog signal, which can be used to connect an analog monitor. The analog pins are the four that surround the flat blade on a DVI-I or DVI-A connector. A VGA monitor, for example, can be connected to a video source with DVI-I through the use of a passive adapter. Since the analog pins are directly compatible with VGA signaling, passive adapters are simple and cheap to produce, providing a cost-effective solution to support VGA on DVI. The long flat pin on a DVI-I connector is wider than the same pin on a DVI-D connector, so even if the four analog pins were manually removed, it still wouldn't be possible to connect a male DVI-I to a female DVI-D. It is possible, however, to join a male DVI-D connector with a female DVI-I connector.

Some DVD players, HDTV sets, and video projectors have DVI connectors that transmit an encrypted signal for copy protection using the High-bandwidth Digital Content Protection (HDCP) protocol. Computers can be connected to HDTV sets over DVI, but the graphics card must support HDCP to play content protected by digital rights management (DRM).


References:

• https://en.wikipedia.org/wiki/Digital_Visual_Interface
• http://www.buildmyowncabin.com/electrical/dual%20link%20dvi%20pinouts.gif