HDMI: The Importance of Termination

For an article about HDMI converters and termination, this was amazingly shallow and uninformative. Not only did the author not mention anything about Low-Skew cabling which would delete the timing issues he mentions, but also seemed to forget the fact that there is a standard for terminating Category cabling according to TIA-568.  Which any installer of cabling systems should be aware of when terminating such cable.

The type of RJ-45 connection should never dictate the quality of the electrical signal on the other side of the cable. Insertion and termination loss should be negligible in the short runs mentioned in the article. The converter itself should also have it’s own automatic (or user driven) compensation settings which should compensate for long runs (of which 50 feet is not).

All in all, I’m not sure of the gist of the article in total. Was this to educate as in inform the general public or further advance the cause of a unstable and even worse unreliable termination?

Kareem you appear to be treating an HDMI install as if it were a standard network installation.
With HDMI over Cat/x this is not the case. There are in fact some HDMI over Cat/x products that use the 568 standard as a general rule however they are not as consistent in their operation as those that use paired colors. Paired colors (into the RJ45) provide not only a more consistent overall length but are easier to terminate. TIA 568 will not provide the same performance as a color paired setup.
As to the differences in RJ45 terminals we have seen a wide range of performance differences, some terminals (such as those that come in the blue/white plastic box form Home Depot) allow the wire to roll around in the slots of the RJ45 and not make good blade contact. We have also found some brands that are not secure when pushed into the receptacle. The other thing to note is that unlike network data (as a rule) HDMI is a redundant data process, if for some reason the data does not make it to the display the source does not resend it “to bad, so sad”.

Note: We sell products designed by Mr. Boccaccio’s company and there was a lot of discussion about if we should use the TIA568 standard. After much testing we decided that the overall performance gain by using paired colors was worth the possible confusion.

FWIW: The article as you see it is not how it was written. CEPro space restraints sometimes require the text to be edited (by CEPro).

It sounds to me like it really isn’t worth trying to use Cat5/6 cabling for HDMI then?!?

Correctly terminated HDMI over Cat/x systems provide a level of future proofing that a standard HDMI cable can not. Data rates are going up (resolution, Bit Rates and refresh rates) and current HDMI cables over 6 meters will have a very hard time supporting this. If you lay in two Cat/6 cables not only are you good for the current requirements but what is coming as well. In the future when HDMI (as we know it) is replaced you need only swap out the ends not the whole cable that is in the wall.

I’m Confused….  The skew that is designed into a Cat5, Cat5e or Cat6 (to prevent cross talk) would create a much larger skew issue vs. how the pins of a RJ45 connect to the pairs of the UTP.

  If there is a argument that the termination of a RJ45 can create skew, then a zero skew UTP cable MUST be used in that argument… otherwise the skew of a Cat6 would far exceed any skew created in at RJ45.

Furthermore, T568 termination should either be a requirement of a extension product, or a custom wire map would be needed.  If the product is designed to use T568(b) termination, then it is looking for the White Green \ Green pair on pins 3 and 6.  If “Colored Pairs” are used as a guideline to terminate the RJ45, then signals which should be paired together might be split between two different pairs.  Splitting the signals between pairs would most likely cause a major issue do to the lack of common mode noise rejection and increase cross talk.

My $0.02