AMX DX-TX-WP-BL User Manual

Cabling for Success with DXLink

Author: Curry Kinyon
Co-Author: Jeff Howes
Co-Author: Ann Yanecek

CABLING F O R SUCC E SS WI TH DX L I NK

White Paper

TM

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CAB LING F O R SUCC E SS WI TH DX L I NK

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Table of Contents

EXECUTIVE SUMMARY .................................................................................................................... 3

INTRODUCTION ............................................................................................................................... 4

Overview ................................................................................................................................................... 4

DXLINK PERFORMANCE .................................................................................................................. 5

Basic Cable Information ............................................................................................................................ 5

Installed Cable Channel Performance ...................................................................................................... 6

Enova DGX Link Quality Reporting ........................................................................................................... 6

CABLE QUALITY ............................................................................................................................... 6

Cable Type ................................................................................................................................................ 6

Internal Channel Parameters .................................................................................................................... 6

External Channel Parameters ................................................................................................................... 7

Cable Shielding ......................................................................................................................................... 7

Cable End Termination ............................................................................................................................. 8

Bandwidth Performance ........................................................................................................................... 9

CABLE TOPOLOGY ........................................................................................................................... 9

Cable Length ............................................................................................................................................. 9

Cable Management ................................................................................................................................ 10

Patch Panels ............................................................................................................................................ 11

Patch Cables............................................................................................................................................ 11

ENVIRONMENT ............................................................................................................................. 12

Grounding ............................................................................................................................................... 12

Electrostatic Discharge (ESD) .................................................................................................................. 13

Electromagnetic Interference (EMI) ....................................................................................................... 14

Electrical Motors ..................................................................................................................................... 14

Proximity ESD Events .............................................................................................................................. 14

Ambient Operating Conditions ............................................................................................................... 15

CONCLUSION ................................................................................................................................. 15

Appendix A .................................................................................................................................... 16

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EXECUTIVE SUMMARY

Cabling For Success with DXLinkTM

After a full year of supporting deployments of DXLink solutions, it has become clear that using
unshielded cable is problematic. Installations with unshielded cable often have reliability issues with
the DXLink connection caused by changing environmental conditions. Therefore, our revised minimum
required cable type for DXLink systems is shielded CAT6 and that it’s installation follow the
recommended guidelines in this document.

DXLink™ delivers 10.2 Gb/s throughput over shielded category cable. It accomplishes this by leveraging
the transport layer of HDBaseT technology.
audio / video content at distances up to 100 meters when properly deployed and configured. The
following white paper provides detailed information on how cable quality, cable topology and the
environment affect the performance of DXLink systems. In summary, suffice it to say that looping, poor
cable end termination, using patch blocks, inadequate grounding of the cable/rack/building and
running cables near noisy devices will negatively affect the quality of the signal path and cause issues
such as offline events and blinking of video. Below are some helpful guidelines to follow when deploying
your DXLink system.

Best Practices

 For best “it just works” results shielded Cat6A cable is recommended
 If you have a cable deployment scheme running many cables in a bundled structure through

conduit or cable trays and have runs that traverse near large EMI or ESD generators you should
use shielded Cat6A cable to achieve reliable 100 meter performance

For optimal performance:

 Keep the cable runs as short as possible
 Follow cable shielding and termination techniques defined in this document
 Follow Equipment and Building Ground requirements defined in this document
 DXLink twisted pair cable runs for DXLink equipment shall only be run within a common building
 Keep the DXLink cables as isolated as possible from noisy power cables
 Avoid running cables in parallel with power runs, try to cross at 90 degree angles
 Avoid running near noisy devices (motors) or inductive loads
 Avoid tie wrapping and/or tightly bundling DXLink cables together
 Avoid making sharp corners/bends in cable runs
 Minimize “coiling” of the cables
 Minimize patch panels & patch cables (every connection introduces losses)
 Make sure connectors are properly terminated, higher quality shielded cables require

more intricate terminations

DXLink is state of the art technology capable of delivering

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INTRODUCTION

A multitude of aspects contribute to the overall system performance of DXLink products when installing
structured cabling solutions. The capabilities of this solution to pass Uncompressed HDMI Video,
Uncompressed HD Audio, Ethernet, Serial, IR and Power require a cable bandwidth of 250 MHz or
greater and cabling infrastructure performance that supports throughput of 10 Gb/s. Based on the
bandwidth required to transmit this amount of information we recommend following industry standard
practices designed for 10 Gigabit Ethernet. In order to perform at its best, the HDBaseT transport layer
utilized in DXLink requires specific rules which include management of not only to the cabling system
back-bone but also the patch locations and end-point runs. The primary focus of this paper is to review
the key challenges and solutions facing the structured copper cabling media required to properly
support the DXLink technology.

OVERVIEW

To achieve a high performing and reliable installation, several key factors need to be considered and
managed which all have a combined impact. When any one of these factors is not adhered to the
likelihood of inconsistent performance or sporadic video, audio and network drop-outs increase, to the
point where the products can fail to function at all if faced with several conditions not being met.

Three main areas need to be addressed in order to optimize the performance of DXLink installations.
They all have a direct impact on the performance of the overall DXLink system and also have relational
impact on each other, such that improving in one area can often provide ability to overcome
shortcomings in one of the other areas. A balancing of these three roles will allow for a successful and
robust DXLink system.

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Cat6A F/UTP (shielded and bonded)
Belden 10GX 10GX62F (Riser)
Belden 10GX 10GX63F (Plenum)

Cat6 F/UTP (shielded cable)
Belden 2412F DataTwist (Riser)
Belden 2413F DataTwist (Plenum)

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DXLINK PERFORMANCE

Depending on the link quality between DXLink devices over structured cabling, the product performance
can vary from a solid and reliable system to a system which may have intermittent problems or links
that fail to function altogether. The most common symptom of poor link quality due to deficiencies in
the structured cabling is intermittent momentary dropping of video and audio but can also degrade to
the point that end-points fall offline and can even cause a link not to function at all, incurring a failure to
link.

This section touches on specific guidelines which can be referenced to ensure success from the
beginning of the project all the way through installation providing validation of link quality after the job
has been completed.

BASIC CABLE INFORMATION

Pre-installation cable selection should be the first order of business when designing the overall
installation. The cable selection should be determined by the combination of these factors: the
environment, the length of DXLink cable runs and the planned cable topology. As shown in this
document they all play a role in overall system performance.

The primary goal is to negate any of the external environmental factors that can impact performance
while ensuring a quality transport path from end-point to end-point. The minimum required cable to
provide a successful system installation is a shielded Cat6 cable. To ensure robust performance in
installations with unmanaged environmental factors, stepping up to Cat6A STP or Cat7 is recommended.
STP is used in this document to cover the wide range of Shielded Twisted Pair implementations listed
below; the severity of environmental factors should be considered when selecting between them:
SF/FTP, S/FTP, F/FTP, SF/UTP, U/FTP and F/UTP

‘S’ represents Screened braid shielding (also sometimes referenced as ‘Sc’)
‘F’ represents Foil shielding
‘U’ represents Unshielded
‘TP’ represents Twisted Pair

And notations left of the ‘/’ defines outer cable shielding while right of the ‘/’ defines shielding of the
individual wire pairs. Some graphical examples are shown on page 8 of this document.

Note: Not all cable manufacturers use the same definitions regarding shielding nomenclature.

For best performance a shielded Cat6A cable is suggested, we recommend the following (or equivalent)
to provide a good price vs. performance point while minimizing environmental impact.

When using a Cat6 F/UTP cable we recommend the following (or equivalent).

A complete Belden shielded Cat6A cable and cable management solution is available here:

http://www.belden.com/docs/upload/CheatSheet_10GX_FT_Shielded_Systems.pdf

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INSTALLED CABLE CHANNEL PERFORMANCE

Once cable is installed there are generally several factors that can affect link quality such as cable
quality, cable termination, grounding techniques, building ground differences, cable length, cable

topology, service loops, patch panel quality and quantity, cable kinks, etc… In order to understand how

the overall cable paths perform from one end of DXLink to the other end of DXLink, you can utilize tools
such as the Fluke DTX 1800 to characterize a number of specifications defined by TIA-568-C.2. Any cable
type chosen should have its end-to-end performance meet the installed Channel Requirements specified
by TIA-568-C.2.

ENOVA DGX LINK QUALITY REPORTING

Another method for determining the link integrity for a given DXLink path is provided if it is connected
to an Enova DGX populated with DXLink Input/Output boards. The Enova DGX 64, 32, 16 and 8
Enclosures can report measured link integrity values which are useful in qualifying the overall system or
troubleshooting paths that are presenting problems. When connected to the Enova DGX Enclosure,
reporting of each DXLink Input/Output port can be captured which presents a decibel value for each of
the four twisted pairs on a given port. If any of these MSE values reports >= -15dB (i.e. -13dB) the link
quality is in a range that can affect performance. See Appendix A for instructions and examples of how
link quality reporting through the Enova DGX Enclosure can be acquired.

CABLE QUALITY

CABLE TYPE

AMX requires as a minimum using CAT6 shielded cable installed per the recommended guidelines in
this document.

As you might expect, the higher the quality of the category cable the more robust the DXLink system will
perform. The gains to be made in this area are improved bandwidth, improved internal channel
parameters, improved external channel parameters and reduced susceptibility to environmental EMI
and ESD events.

When using Cat6 STP, Cat6A STP and Cat7 which meet their correlating TIA-568-C.2 performance
requirements, the DXLink runs can fully reach the 100m specification when bundled in groups of 6+1
(TIA-568 Alien Crosstalk Bundle). Using the heavier shielded versions of them, such as S/FTP, provide
improved resistance to uncontrolled environmental EMI and ESD events.

The benefits of these increasing grades of cable type provide significant improvement in both internal
and external channel parameters. Specifically of note are:

INTERNAL CHANNEL PARAMETERS

Insertion Loss / Max Attenuation: The measure of signal loss that occurs from transmitter to



receiver.

o

Often referred to as the cable bandwidth, typical factors that affect insertion loss include
conductor size, insulation and jacket material type, frequency bandwidth, number of patch
connections and cable length.

Return Loss: The measure of how much signal gets reflected back to the source due to impedance



variations in the Channel.

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