HDMI cable maximum length
When setting up a courtroom for an electronic presentation, you might think that having a very long HDMI cable would work to your advantage. It could give you more flexibility about where you position your tech table from the inputs for the audio-visual system. There are certainly a lot of very long HDMI cables available of 50 feet,
100 feet . . .
. . . and longer
But with HDMI cables, longer is not necessarily better. HDMI cables may be active or passive. A passive HDMI cable will allow signals to be sent in both directions. An active HDMI cable only allows data to go in one direction, and will include a processor. An active HDMI cable will get power from the device it is connected to. At a length of more than 25 or 50 feet a passive HDMI cable will no longer transmit video and document images with maximum speed and clarity.
More sophisticated audio-visual systems may route an HDMI signal from a computer with Cat 5 or Cat 6 network cables and then pass through to an HDMI cable for a display in order to prevent significant lag over long distances.