HDMI: Cat 568A or 568B Cables Better?
Trying to figure out which cable you should be using? Here is what you need to know when deciding between Category 568A and B.
By Jeff Boccaccio

Someone asked if it was better to use Category 568A or 568B with HDMI. The short answer: neither. Any high-speed engineer learns early in his career that going direct and straight is the best. So why would manufacturers use a 568A or B wiring scheme?

You are the reason. They know that you are familiar with 568A or B and to use it for high-speed HDMI would require you to learn terminating RJ45s in sequential pairs, not 568.

So the bigger question is why are you trying to apply telephone and/or Ethernet applications to HDMI? My guess is that the wire looks the same, the connector looks the same, so why not terminate the same. That’s where the similarities end.

The connector that we typically use for Cat 5 ATD (balun) is an RJ45. This came from a family of connectors ranging from RJ11, RJ25, RJ61, etc. created to standardize telephone-related wires.

When introduced, the quality of the RJ connector was so impressive the FCC even incorporated it into its Part 68 rules. The RJ11 is a 6-pin device and can come in different arrangements for one, two or three analog telephone lines.

However, four analog voice lines used an 8-pin connector called the RJ61. The RJ45 term was essentially decided on by the EIA/TIA to be used for Ethernet, but it became the standard for both voice and data, and so came the 568 standard.

Here is where it gets interesting. Under 568A the two center pins 4 and 5 were isolated by splitting the orange pair to pin 3 and 6, trapping the blue pair on pin 4 and 5 and reversing its

About the author
Jeff Boccaccio - President
Jeff Boccaccio, president of DPL Labs, can be reached at either [email protected] or [email protected]

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