Digital Visual Interface. A standard created by the Digital Display Working Group (DDWG) to enable analogue and digital display devices to be used with a single connection cable and to allow the video signals to be sent to the display device digitally. By transmitting the signal digitally there is none of the quality degradation associated with the analog to digital and back again conversion. So, if you have a source device with DVI and a display with DVI then everything can remain within the digital realm.

DVI-D Socket	DVI-I Socket