There are many situations where an audio/video signal is sent from one device to another over a cable. Examples include computer to video screen, set-top box to video screen, Blu-ray player to home theater amplifier, etc. CTA-861-G describes how to do this with digital signals. When connected devices are turned on, they exchange information about their capabilities, enabling them to work with the highest quality signal that they’re both able to work with. For example, if a DVD player capable of producing 4K Ultra HDTV is connected to a display that’s only capable of HDTV, the DVD player will know to send HDTV content to the screen. Several well-known standards use the technology described in CTA-861-G and add their own enhancements to it. HDMI® and DisplayPort® are two of these. CTA-861.5 describes updates to CTA-861-G that change the way devices exchange information about the audio formats they support.
