Compatibility
The Apple Display Connector, first debuted in the Apple Studio Display, is physically incompatible with a standard DVI connector, as was previously used in the PowerBook G4 and the older Power Mac G4. The Apple DVI to ADC Adapter, which cost $149US at launch but was in 2002 available for $99US, takes USB and DVI connections from the computer, together with power, and combines them into an ADC connection, allowing ADC monitors to be used with DVI-based machines.
The initial implementation of ADC on some models of Power Mac G4s involved the removal of DVI connectors from these computers. This change necessitated a passive ADC to DVI adapter to use a DVI monitor.
The ADC carries up to 100 W of power, an insufficient amount to run most 19-inch or bigger CRTs widely available during ADC's debut, nor can it run contemporary flat panels marketed for home entertainment (many of which support DVI or VGA connections) without an adapter. The power limit was an important factor for Apple to abandon ADC when it launched the 30-inch Apple Cinema HD Display. Power is supplied to the ADC port by a finger connector on the video card, which plugs into a slot on the motherboard between the AGP slot and the back panel of the computer.
On newer DVI-based displays lacking ADC, Apple still opted for a single "ganged cable" that connects the separate signal cables to each other so they cannot tangle. Such cables, however, employ standard DVI, power, USB and FireWire connectors, avoiding drawbacks to ADC. As of 2011, Apple no longer uses a DVI-based interface for any of its displays, preferring the increasingly common DisplayPort signalling standard.
Apple no longer supports ADC adapters, or monitors.
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