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3 Tips for Installing Cat 5/6 HDMI Systems

Here are simple rules integrators should follow when installing Cat 5 or 6 systems.


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Data shows that the deployment of Cat 5/6 HDMI converting systems continues to explode.

Cat 5/6 cables can be field-terminated, while HDMI cables cannot — not to mention the fact that Cat cables are pretty damn easy to install.

Despite the positive data, there have been issues. Here are some simple but important rules integrators should follow when installing any Cat 5 or 6 systems.

Always be aware of timing problems. This involves our old friends, inter and intra pair skew limitations. Cat 5/6 are twisted pairs. They are just as easy to pull, pinch, stretch, and distort during installation.In many cases, the damage comes easier than with HDMI cable. These distortions with the cable can cause server timing and ISI (Inter Symbol Interference) issues, which can cause sparkles or intermittent video. Be careful installing Cat 5/6.

Use Cat 6 if you have the option to choose between the two. Studies have proven Cat 6 will offer almost twice the distance you would normally get with Cat 5. Plus, Cat 6 is built with an inner sheath that keeps each twisted pair separated and flexible — if you do pull it the wrong way, each twisted pair inside can move easier.

Although video integrity is important in any of these converters, don't forget about the DDC serial channel. Our tests have proven that over Cat 5/6 the data on this channel can be easily lost due to rise time issues. That means a high probability of EDID and HDCP failure.

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Article Topics

News · Wire and Cable · HDMI · Wire And Cable · Hdmi · All topics

About the Author

Jeff Boccaccio, President, DPL Labs
Jeff Boccaccio, president of DPL Labs, can be reached at either jeff@invisionstech.com or jeff@dplrating.org.

7 Comments (displayed in order by date/time)

Posted by DrFlick  on  02/12  at  08:38 AM

Jeff,

Since you are talking about using CAT-5/6 for HDMI Extenders and not for Ethernet networking in this case, I am surprised you did not talk about your usual recommendation of using a different wire order for the terminations.  Since you actually are using the pairs as differential wires, terminating them using a “straight through side-by-side” order works better than terminating them using TIA-568-A/B where you actually are separating the wires within a twisted pair.  By keeping the pairs together from very end to very end, you minimize noise and crosstalk, thus extending the range and providing better signal.  Of course, this assumes the active HDMI components at each end are wired as side-by-side wire pairs, which one always should check before installing these products.

  =D-

Posted by rusgrafx  on  03/09  at  05:14 PM

“Cat 5/6 cables can be field-terminated, while HDMI cables cannot” - is no longer a true statement.

Read CE Pro article:
http://www.cepro.com/article/terminate_hdmi_cables_in_the_field_audioquest_solves_hdmis_biggest_challeng/

Posted by paul  on  10/02  at  04:19 AM

would qualifications do you need to install cat5/6 cables in a work enviroment

Posted by paul  on  10/02  at  04:24 AM

what qualifications do you need to install cat5/6 cables in a work enviroment

Posted by DrFlick  on  10/02  at  05:11 AM

I do not understand the question.  Are you referring to the qualifications an installer should have to run the cables in a commercial environment or are you asking about how to do a design for an HDMI-based wiring infrastructure for a commercial building.  I bet most commercial infrastructure wiring contractors would have no idea about the latter.  It definitely is a different set of requirements than doing a “standard” Ethernet layout.  As an FYI, Lowell has some really nice Decora-style 19” plates (in 8 or 9 ports) to use for terminating the HDMI extenders in a rack (http://www.lowellmfg.com/technical/RackSpecs/1b-103 RMP Series rack device panels.pdf).  I would start there and work out to the wall plates using the dual CAT-6 approach.  Do not forget to run an extra pair of at least 22-gauge wires to the receiver location for power so you do not need to put a wall wart there (you should look at some of the appropriate industrial DIN rail power supplies for driving a series of them).  If you need to cover long distances, put sub panels closer to the endpoint locations and use HDMI fiber extenders to link the locations together (or use fiber from a central spot).  Of course, that assumes you put some sort of HDMI matrix switcher out in those closet racks, too.  If it is a very large installation, I would look at using fiber runs from a centralized location rather than focusing on a dual CAT-6 solution.

  =D-

Posted by micah  on  11/20  at  11:08 AM

Is there a specific color pattern that must be followed to connect cat5/6 to hdmi converters.

Posted by DrFlick  on  11/20  at  12:57 PM

It depends upon how the vendor implemented their products.  Our recommendation usually is that you wire them “straight through,” which means NOT EIA/TIA-568-A or B.  This is especially important for implementations using dual CAT-6 (or CAT-5) cables where one of the cables has the four TMDS lines (red, Blue, Green, and Clock).  It is critical that these differential pairs are EXACTLY the same length and that the pairs stay twisted as closely together as possible.  Otherwise, you will induce timing delays, which lead to problems when using them in practice.

The actual colors are not as critical, but we tend to just not “crossover” the orange and blue colors used in a normal TIA termination.  We simply wire 1 to 1, 2 to 2, 3 to 3, etc.  We also keep the twists twisted as close to the end of the wire as possible to maintain the “differential” part of TMDS as possible.

  =D-

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