HDMI over Cat6 converters are used to extend an HDMI signal. While some HDMI cables are produced to be 30 metres or longer, typically a signal run through that length is significantly weakened. To maintain the quality of your home theatre system, use an HDMI over Cat5e or Cat6 for a stronger, more reliable connection. These are used similarly to HDMI splitters, switches, and converters. You will need two boxes, as the connection will start in HDMI from your DVD or bluray player, convert to Cat5e or Cat6, and return to HDMI at the receiving end. These products extend high definition displays, making them essential for larger home cinema systems, and also have a built in equalizer to adjust picture quality.