Ormond Beach, Fla. — DPL Laboratories has published a whitepaper to guide installers on when and how to distribute HDMI signals through CAT-5/6 cables over long wiring runs.
DPL, which certifies the performance of HDMI connections and cables, is making the whitepaper available free of charge to installers who sign up to join DPL’s mailing list.
The whitepaper, written by DPL president Jeffrey Boccaccio, includes proper installation techniques needed to ensure the highest resolution and reliable performance. One technique is to keep the CAT cables as far as possible from sources of electromagnetic interference, including electrical wires, lighting fixtures, and transformers.
“The utilization of Category 5/6 cables as an HDMI connectivity solution has grown astronomically over the past two years,” the company said, “primarily because it provides a means for installers to field-terminate exact-length cables.” Dedicated HDMI cables generally do not allow for this capability, DPL said.
One challenge, DPL noted, is ensuring that intelligence data, including HDCP copy-protection data, is shared between source and display. In transmitting HDMI-over-Category cabling, “we are asking the HDMI intelligence data to travel down a transmission line for which it was never intended or designed,” DPL warned.
Another challenge is ensuring that low-current voltage of a minimum 4.7 volts reaches the display despite cable resistance that rises with longer lengths. Installers must also be sure that each signal wire within a cable is the same length to precisely coordinate the arrival of red, blue and green video data.