DescriptionAppleAudioVision 14 Display Adapter590-0793-ARetail Part # 922-0419 (part of the M1243LL/A kit)
This adapter that allows you to use the AudioVision monitor with any Mac with a DB-15 monitor port. It allows you to bring in audio, video and adb. All of which is automatically taken care through the HDI45 port on the 6100/7100/8100 series.
Here is an excerpt from: What is the Integrated Desktop Cable (IDC)?
A: It’s a new high-density cable for plug-and-play set-up. The IDC 
replaces five cables that would normally have to run from your computer
 to your display to provide the same AudioVision functionality (sound-in,
 sound-out, ADB, video-in, video-out). Now with a single “snap” you’ll
 be connected.


Q: When do I need the AudioVision Adapter?
A: It is required on all modular Macintosh models that do not have the
 high-density connector on the back panel of the computer. The part
 number is M1243LL/A. Future Apple CPU’s will support the new integrated
 desktop cable and, therefore, will not require the AudioVision adapter.”
Box Medium 172