HDMI Cables form part of a fully digital connection system that carries both video and audio. HDMI can also be connected to DVI using HDMI to DVI cables or an adapter. HDMI to DVI cables can be used in either direction so could can equally be called DVI to HDMI Cables. DVI does not normally carry audio although some PC video cards now support DVI audio using an SPDIF loop through.
HDMI splitters allow one HDMI source to be connected to multiple screens displaying the same signal using multiple HDMI cables, HDMI switches allow multiple devices to be switched to a single HDMI input. The 4 x 4 HDMI matrix switch allows any of 4 HDMI signals to be connected to any 4 display devices making a truly flexible system