We have found and have confirmed with many integrators and installers, that HDMI cables exceeding 15’ can be unpredictable in performance depending on the cable quality and the source and sink devices. We know that longer copper cables introduce more electrical resistance/signal attenuation, which can cause issues with signal integrity. In addition, the hot plug detect signal is essential for HDMI and this signal is dependent on the capability of the source to provide a proper voltage level and for the sink to have the capability to detect the signal. An installation may work with a long cable today, but when the source or sink is replaced, the installation may not work anymore. This causes a truck roll. We are hearing this more and more where our customers simply do not use cables longer than 15’, and for any longer applications they immediately go to active extenders over Category cable for a reliable long-term connection. We want our systems to be rock solid for our customers over the long term, so this is why we limited our cable offering to a maximum of 15’.
I will also refer you to the learning center pages on the HDMI.org site (http://www.hdmi.org/learningcenter/kb.aspx?c=7 and http://www.hdmi.org/learningcenter/kb.aspx?c=7#144). There you will find additional information regarding the capability and classifications of HDMI cables. Note that High Speed (Category 2) cables are needed for support of 1080p signals at increased color depth and increased refresh rates and for 4K 2160p signals. HDMI.org indicates maximum length for Category 2 cables to be 5-8 meters (16’-26’), but performance and reliability are dependent on cable quality and wire gauge. Our HDMI cables are high quality certified High Speed HDMI Cables with Ethernet and Audio Return Channel and they support 4K signals. As customers upgrade from 1080p to 2160p there can be issues with existing cables and longer cable lengths. Again, this is why we have limited our cable offering to 15’ maximum because we want to ensure a long term reliable system.