Apple Display Connector
A proprietary video interface introduced by Apple Computer with the G4 Cube, it has appeared on every Powermac since.
The ADC connector is actually a superset of the DVI interface, though not backward-compatible. ADC carries a standard DVI video signal on its pins, accompanied by power and USB pins. This gives the advantage of a single cable connecting the CPU and the display, while allowing the CPU to power the display and allowing the display to incorporate USB ports.
As of August, 2002, all of Apple's displays have ADC-terminated cables, and can only be used with an ADC video card, though DVI to ADC converters have recently become available, which consolidate separate DVI video, power and USB inputs into a single ADC output.
nVidia and ATI currently manufacture ADC video cards as original equipment for Apple's Powermac line (as of 7/2002 the nVidia GeForce 4 MX and GeForce 4 Ti are available, as well as ATI's Radeon 7500 and 8500).