A method and device for operating a data link having multiple data lanes is provided. The method includes supplying first data (such as video data that follows the DisplayPort protocol) on one or more data lanes of a data interface between a video source device and a video sink device. In addition to being video stream data (such as the above mentioned DisplayPort video data) the first data can also be audio stream data (such as DisplayPort audio data), source-sink interface configuration data (such as DisplayPort AUX data) and sink related interrupt data (such as DisplayPort Hot Plug Detect “HPD” data). The method also includes receiving second data on one or more unidirectional data lanes of the data interface. The second data being data other than video stream data, source-sink interface configuration data and sink related interrupt data.