DDC stands for Display Data Channel. DDC was created by the Video Electronic Standards Association (VESA) and it is a digital connection between a source device and a display device, like a computer graphics card and a computer monitor. It is used for the transfer of specification data from the display device to the source. The information is generally stored on an EDID ROM chip included with the display device.
The DDC standard is in use with the VGA, DVI and HDMI connection standards. The Digital Rights Management (DRM) standard known as High-bandwidth Digital Content Protection (HDCP) - used to protect High Definition video data as it travels between devices from being copied - utilises the DDC channel to initiate a handshake between a source device (like a HD DVD player) and a display (HD Television).