An HDMI extender is a device that extends the distance between your television and any HDMI-compatible device. It is comprised of a single transmitter and receiver that sends high-quality video and audio signals from one device to another. HDMI extenders convert the HDMI connection to Ethernet, and then back again at the other end. This lets you run a connection to one or even multiple displays hundreds of feet away. HDMI extenders use LAN cables for distributing signals over a broader range.