iMac (17-inch Flat Panel): About the VGA Port

The iMac computer has a mini-VGA monitor port located on the rear of the computer in the I/O port area.

Figure 1. iMac (17-inch Flat Panel) rear I/O port area.

This port allows you to use the iMac's video mirroring feature with a compatible VGA monitor. Video mirroring allows you to see on a second monitor the same image you see on the iMac's flat-panel display. This feature does not allow you to extend the iMac desktop with the external monitor. An Apple VGA Display Adapter, part number M8639G/A (available separately), is required to plug in the monitor cable.

The video mirroring feature is 'plug and play'. Connect your monitor to the Apple VGA Display Adapter, then connect the Apple VGA Display Adapter to the mini-VGA port located on the back of the computer. When connecting the Apple VGA Display Adapater to the computer, the screen may refresh for an instant as the machine
reconfigures for video output.

Any VGA monitor that is compatible with these resolutions and frequencies can be used:

The computer will attempt to match the resolution of the built-in and external display. If there is no way to match, the computer will change both screen resolutions and may black out areas on the built-in display in order to compensate for the capabilities of the external display.

You can switch resolutions and frequencies in the Displays Preference Pane of Mac OS X System Preferences, or in the Monitor control panel of Mac OS 9.

For connecting displays that use another type of connector, or requires a resolution and frequency that is not compatible with the iMac, you can use a third-party scan converter in conjunction with the Apple VGA Display Adapter. To learn what scan converters are available for Macintosh systems, see the Macintosh Products Guide at (http://guide.apple.com/) for the latest devices.

Apple DVD Player for Mac OS X supports DVD playback through external video mirroring. DVD playback is automatically set to play on the external VGA display connected to the Apple VGA Display Adapter when opened. Apple DVD Player for Mac OS 9 does not support this feature. You should disconnect any external display when playing DVD video in Mac OS 9.

Important: The Apple VGA Display Adapter (M8639G/A) should not be confused with the Apple Video Adapter (M8734G/A). The Apple Video Adapter (M8734G/A) is not compatible with the iMac mini-VGA monitor port.