The HDMI interface is electrically identical and compatible with the video-only DVI interface, which came before. For example, if a cable box or PC has DVI out, but the TV or monitor only has HDMI in, a DVI-to-HDMI adapter cable is used to connect the video. The audio must be cabled separately as DVI transfers only video. HDMI detects DVI on the other end and switches to the DVI protocol. See HDMI and DVI.
HDMI and DVI Plugs
Both HDMI (left) and DVI (right) have 19 pins, yet HDMI handles video and eight channels of audio, whereas DVI is video only. DVI-to-HDMI and HDMI-to-DVI cables provide the video compatibility.
This TV Has HDMI In
If the cable box has HDMI out, then only one HDMI cable is used to hook up this TV. However, if the box has DVI out, then a DVI-to-HDMI cable connects the video, and the audio is wired separately using left (white) and right (red) analog stereo connections.