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CAT5 SmartWired Surge Protection Systems
TM
April 22, 2015
What is CAT5 SMARTWIRED
Table of Contents
TM
Introduction ............................................................................................................................................................................ 3
Traditional POTS vs. High Speed Data Outside Plant Connectivity and Protection ................................................................ 3
High Speed Data Wiring and Terminating............................................................................................................................... 4
LEA Networks Protector Block, Making Smart Wiring Possible .............................................................................................. 4
CAT5 SMARTWIRED Protection Systems .................................................................................................................................... 6
Attenuation and Crosstalk Performance ................................................................................................................................ 6
Summary ................................................................................................................................................................................. 8
Glossary ................................................................................................................................................................................... 8
References .............................................................................................................................................................................. 9
About the Author .................................................................................................................................................................... 9
About LEA Networks ............................................................................................................................................................... 9
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Introduction
Current high speed transmission standards like ADSL2+, VDSL2, and Ethernet in the First Mile (EFM), require increased
performance from wireline outside plant connection and protection equipment. The cables themselves, most notably
multi-pair Category 5e, have been refined over the years to improve pair-to-pair crosstalk and signal loss. It’s even
become common to use fully shielded cable in high density data service areas, such as remote DSLAM enclosures to
mitigate noise. Two increasingly common situations can quickly reduce Category 5e, or any cable data transmission
abilities:
1. The number of active high speed lines within any span or connectivity point.
2. Increased transmission frequencies on individual pairs within any span or connectivity point.
Coping with these two situations, or worse, the combination of the two, requires a rethinking of copper connectivity
products and how they’re used. CAT5 SmartWired™ is LEA Networks’ design philosophy to ensure maximum bandwidth
in modern telecom data systems.
Traditional POTS vs. High Speed Data Outside Plant Connectivity and Protection
Until the late 1990’s, telecom connectivity hardware designs were focused on long term reliability, robust designs, and
some attention to cable and wire routing. The connections themselves were entirely focused on simplicity and strength
(e.g. binding posts, screw terminals & wire wrapping). Primary protection connector blocks were designed for ease of
manufacturing and long term reliability. In the absence of transmission concerns, safety and reliability were rightfully
the top concerns. Protection systems saw a gradual shift from traditional 5 pin gas discharge tubes to solid state based
technology. This gave better equipment protection, and solved the problems of high variability with gas tube
manufacturing.
In the early 2000’s, transmission testing showed that traditional 5 pin connection blocks were capable of Category 5
(100MHz) hardware component performance levels, the same as a standard RJ-45 LAN jack. Wiring was still largely
voice-grade or Category 3. Connection and termination technologies did begin a gradual shift towards ease of use
(insulation displacement connectors) and transmission quality. The enterprise infrastructure led the way with the
proliferation of Category 5 and later, Category 5e structured network architectures. However, the OSP delivering data
services was still reliant on T-1 for business and data centers, and ADSL was limited to possibly 6Mbps under ideal
conditions. The connectivity and protection hardware didn’t require much change of design or use. Easy improvements
in attenuation were made by changing back to (modernized) gas discharge tube modules.
DSLAM remote terminals and Central Offices eventually showed the first weak link in the twisted pair plant. While the
speeds weren’t yet very high, the density of active pairs within any one cable or running through a connection block was
increasing. The issue wasn’t attenuation; it was the crosstalk within the tight bundles of active signal pairs. Soon
enough, Category 5e cable became the norm in high density data pair systems. Even though the length of cable in a
remote terminal is only several feet, the crosstalk contribution can eliminate the ability to transmit high speed signals
over long distances.
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To understand this fully, it’s important to know that crosstalk isn’t as simple as attenuation, which generally goes up
smoothly as the span distance increases. It’s dominated by the cable itself in most spans. The total crosstalk in a data
channel is the sum of the crosstalk contributions from all the individual elements, or disturbers. The total crosstalk can
easily be dominated by one element. A Category 3 jack used in a Category 5e channel will cause the whole system to
run at Category 3 speeds. This is the reason that LAN system components (cables, connectors, patch panels & patch
cords) are all certified to a specific Category capability. In order to function at Category 5e speeds, everything needs to
perform at Category 5e crosstalk levels.
Crosstalk is the now the major limiting factor in high speed telecom data delivery. Crosstalk is dominated by the
connectivity, cabling, and line (connection) conditions.
High Speed Data Wiring and Terminating
Like fiber optic systems, twisted pair wiring for high speed data requires a few special precautions. The general methods
are listed below, and what not performing them correctly can cause.
Minimum Bend Radius
Trimming Wire Pairs
Wire Untwist
Pair Separation/Isolation
Guideline
Minimum 10X cable diameter
Issue
Sharp bends can create localized
crosstalk hotspots, and if severe
enough, an issue with extra reflection
losses.
Trim tip/ring as evenly as possible
Uneven
lengths
can
create
longitudinal imbalances, which adds
noise and decreases effective speeds.
Never leave more than 0.5” of Category 5e wire Open loops create crosstalk hotspots
pair untwisted. If more is required to make a to adjacent pairs.
termination, re-twist pairs after the connection is
made
Keep wire pairs away from adjacent terminations Termination
points
are
more
as much as possible; use guide rings or loose tie susceptible to crosstalk since pairs are
wraps in common areas
opened up; this can cause spikes in
crosstalk
LEA Networks Protector Block, Making Smart Wiring Possible
LEA Networks engineering, having been in design and development of wireline protection and connectivity for decades,
knew that all the existing supplier’s legacy 5 pin protector blocks were designed for ease of manufacturing, but not
transmission. LEA Networks goal was to design a block with the same features and protection performance, but
optimized for modern data transmission. Using the aforementioned guidelines for proper high speed wiring, LEA
Networks redesigned the 5 pin protector block from the ground up.
To enable this goal, a shortened module socket was designed, since the straight socket is the same as open untwisted
wire. Next, the line and equipment sockets were re-oriented to minimize Tip-to-Ring wire wrap distance resulting in the
following benefits:
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Untwisted wire pair and tip/ring open loop area are minimized which reduces crosstalk and attenuation.
2. Adjacent pair to pair distance is increased, which also reduces crosstalk.
3. The free space for wire routing is now between the rows, not down the middle of tip/ring pairs. This is perhaps
the biggest benefit since it prevents adjacent untwisted wire pairs being threaded down through each other, a
major cause of crosstalk.
Guide rings were added to enforce proper grooming while cables are wire wrapped into place. The diagram below
illustrates the new LEA Networks wired block compared to nearly all existing blocks.
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CAT5 SMARTWIRED Protection Systems
LEA Networks protection block was designed to maximize high speed transmission performance to Category 5e levels.
Wiring with anything less than Category 5 cable would defeat the performance gains, so all LEA Networks Protection
Systems use minimum Category 5 internal cable. Internal wiring methods adhere to all the high speed wiring guidelines
to ensure optimum performance.
So, what is CAT5 SmartWired?
- A lightning protection system built using a high speed optimized protector block, Category 5 minimum rated
cabling, and manufactured using strict high speed wiring methodologies.
Maybe I don’t need CAT5 SmartWiring, so why pay a premium?
- There is no premium. By only producing high speed compatible systems, LEA Networks is able to leverage its
volume with standardized designs and material usage. Even if your current system requirements don’t need it,
chances are you eventually will. When you really need to maximize your transmission performance, there’s no
“enhanced” special part numbers (or pricing), every system is designed for high speed performance.
Attenuation and Crosstalk Performance
The current Telcordia telecommunications hardware transmission standards and the latest EIA/TIA 568-C standards for
Category 5e serve as guidelines for high speed testing. Below are independent laboratory tests of LEA Networks
protection block system wired with 1m of Category 5e cable, the same cable used in all protection systems LEA
Networks manufactures. Crosstalk is measured using Power Sum NEXT, to give a real world idea how the system
performs with multiple active data lines.
In the Insertion Loss graph, the red line shows the Category 5e requirements for a connector, such as an RJ-45 jack. The
protector block, even with 1m of cable barely shows any attenuation.
The crosstalk graph shows PSNEXT in 5 representative positions on a 50 pair system. The worse case measurements on 4
simultaneous pairs are within 5dB of the Category 5e requirements for one pair. The best case is good enough to meet
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the Category 5e requirements for one pair. Return Loss and Longitudinal Balance performance (not shown) are
comfortably within Category 5e ratings.
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Summary
As data delivery protocols evolved from analog POTS to today’s VDSL2 speeds, the performance of the outside plant
network has had to improve dramatically. Legacy POTS era equipment wasn’t designed to minimize crosstalk, return
loss and attenuation, which can all significantly deteriorate the ability to reach the needed distances with reliable data
rates. Implementing transmission optimized OSP equipment is essential to maintain the rate reach performance
required for today’s media, since even one significant crosstalk disturber can have immediate and obvious affects.
LEA Networks has reset the performance expectations of standardized twisted pair protection with a ground up redesign
of the heart of all lightning protection systems, the 5 pin protector block. Combined with a disciplined methodology for
wiring and grooming, allows LEA to produce truly state of the art protection and connectivity systems.
Glossary
Attenuation - also known as Insertion Loss, is a measure of the strength of a signal at a remote point, compared to the
original signal strength transmitted. It’s measured in negative decibels (dB’s), representing a ratio of the remaining
signal vs original signal. Every 6 dB equals half signal strength, so -6dB is 1/2 strength, -12dB is 1/4, -18dB is 1/8, etc.
Attenuation goes up as the transmission speed increases.
Crosstalk - this occurs when the signal from one pair is induced into another pair, causing signal distortion and
degradation. The terminating equipment can’t tell the difference between the two streams, so bit errors increase. It’s
also measured in negative dB’s, as a ratio of the unwanted signal compared to the desired one. So, a smaller negative
number means more crosstalk (the unwanted signal is becoming as big as the desired one). Crosstalk also sets worse as
the transmission speed increases.
PowerSum Crosstalk – this is crosstalk, but measured by adding the crosstalk from 3 adjacent pairs. This shows how a
loaded cable or connection point acts when multiple signals operate at the same time.
Attenuation-to-Crosstalk Ratio (ACR)- this measurement is frequently used at a termination point or subscriber location
as a single number to represent line quality. It’s simply the attenuation minus crosstalk, and the bigger the number the
better (i.e. less attention and higher crosstalk rejection). This is particularly important when dealing with longer spans
and higher bit rates, where attenuations and crosstalk numbers can be significant. It is entirely dependent on
transmission speeds, so just because a line handles a 1.2Mbps ADSL signal doesn’t mean it can handle 35Mbps VDSL.
Primary Lightning Protection – an over-voltage protection device used to prevent personnel injury and equipment
damage from lightning, AC power faults, etc. They are generally used on either end of any copper pair span that is
susceptible to transients, and is mandated by the National Electric Code to be used at every building or service location
occupied by people. It’s termed “primary” because it’s the first and frequently only line of defense.
5 Pin Protection Module/Connector Block – the predominant form factor for primary protection on twisted pair
communications cables in the US, Canada, Mexico, and some South and Central American countries. The plug-in
modules and connecting blocks are standardized to ensure continued viability of the supplier base, and future-proofing
for replacement protection devices.
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Building Entrance Protector (BEP)- a standardized system to terminate outside plant cables, provide primary protection,
and a subscriber side (or equipment) cable connection point. This also presents a demarcation and field/equipment side
test access. An internal fusing mechanism permanently disconnects the equipment connector from the outside line
connector to isolate the personnel during catastrophic or sustained faults.
References
TIA-568-C.1, Commercial Building Telecommunications Cabling Standards - Part 1 General Requirements, Revision Date:
02/02/09
TIA-568-C.2, Balanced Twised Pair Telecommunications Cabling and Component Standards, Revision Date: 04/00/10
NFPA 70: National Electric Code (NEC), 2008 Edition
About the Author
Allen Gara is the Engineering and Operations Manager for LEA Networks. He has more than 20 years of experience in
research, design, and development of telecom lightning protection and connectivity systems. For more information,
email [email protected].
About LEA Networks
LEA Networks is a worldwide provider of xDSL splitters/filters, Power Line Carrier (PLC), Primary Surge Protection and
connectivity systems for the telecommunications industry. The company researches, designs, markets, and distributes a
wide range of standard and custom products, which have been deployed by over 150 carriers
worldwide. Headquartered in Skokie, Illinois, LEA Networks is a wholly-owned subsidiary of HF Company (NYSE
Euronext: HF).
USA
LEA Networks, LLC
5500 W. Touhy Ave, Suite P
Skokie, Illinois
60077 USA
Phone: +1.847.673.1853
Fax: +1.847.673.2153
lea-networks.com/americas
France
LEA SAS
Immeuble Le Linéa
1 rue du Général Leclerc
92047 Paris La Défense Cedex
Phone: +33 (0) 1.49.97.05.30
Fax: +33 (0) 1.49.97.05.31
China
LEA Technologies Ltd
Tianan Hi-Tech Plaza Tower A
Futian District, Shenzhen
PRC 518048, China
Phone: + 86.755.8287.6321
Fax: + 86.755.8287.6331
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