The Micro-DVI port is a proprietary video output port found in the original MacBook Air. It is smaller than the Mini-DVI port used by its MacBook models.
To use the port for displaying video on a standard monitor or television, an adapter must be used. Both a Micro-DVI to DVI adapter and a Micro-DVI to VGA adapter was bundled with the original MacBook Air. A Micro-DVI to Video adapter, which provided composite and S-video outputs, was also sold separately. The Micro-DVI to DVI adapter is only compatible with a DVI-D (digital) signal; DVI-A and DVI-I signals do not work as they do not have the required analog connections.
The Micro-DVI connector was replaced with the Mini DisplayPort connector starting with the Late 2008 MacBook Air.
Additionally, the Asus U2E subnotebook includes a "Micro-DVI" port.
Although it is electrically compatible with HDMI, it does not provide audio output.