a DVI-to-HDMI adapter cable is used to connect the video. The audio must be cabled separately as DVI transfers only video. The HDMI circuit detects the DVI signals and switches to the DVI protocol.

HDMI cables can pass video, audio, and limited control signals ... HDMI can also be used with other connections, such as DVI, USB-C, MHL, and DisplayPort via adapters. Most HDMI cables are ...

[purisame] has eschewed simply outputting compatible DVI signals on the port. This implementation is pure HDMI 1.4b, enabling the extended capabilities this brings, like combined video and audio ...