Mini-VGA connectors are proprietary and non-standard alternative video connectors that were used on some laptops and other computer systems in place of a standard VGA connector. Apple, HP, and Asus each introduced separate connectors using the same moniker of "mini-VGA", but which are otherwise physically incompatible with each other (though all of them are compatible with standard VGA using the correct adapter).
Apple's mini-VGA ports may be found on some older Apple computers, including iBooks, eMacs, certain PowerBooks (e.g., early G4 12-inch), and some iMacs (e.g., iMac G4, G5). In addition to a more compact form-factor, Apple's mini-VGA ports also have the added ability to output composite as well as S-Video, in addition to VGA signals, through the use of EDID. When used for S-Video, S-Video's chrominance (C) and luminance (Y) signals replace VGA's red (R) and green (G) channels, while for composite video, the signal is output through VGA's blue (B) channel. (The horizontal and vertical sync pins of VGA are left unused.)
