The Display Data Channel (DDC) in HDMI is a communication protocol that enables communication between HDMI source devices (such as computers or players) and HDMI sink devices (such as displays or televisions).
DDC plays a pivotal role in the HDMI interface, primarily serving two key functions:
1. EDID Reading: DDC is used by the source device to read the EDID (Extended Display Identification Data) of the sink device. EDID contains performance parameters and capability information of the sink device (such as a monitor), including the maximum supported resolution, color depth, refresh rate, etc. After obtaining this information through the DDC channel, the source device can automatically configure the output signal to match the optimal settings of the monitor.
2. Control data exchange: In addition to transmitting EDID, DDC may also be used to transmit other control data, although this is not as core as EDID in the HDMI standard. For example, in some cases, EC (Consumer Electronics Control) functionality may also utilize the DDC channel to achieve interactive control between devices.
