1.3 Field Testing Update
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Transcript of 1.3 Field Testing Update
8/13/2019 1.3 Field Testing Update
http://slidepdf.com/reader/full/13-field-testing-update 1/38
Field Testing Update
Adrian Young
Fluke NetworksNovember, 2013
Singapore
8/13/2019 1.3 Field Testing Update
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Objectives for this session
• Copper field standards update
• Look at new copper field measurements
• Fiber field standards update
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IEC 61935-1 Ed.4
• Defines field tester accuracy for ISO/IEC 11801:2010 – Level IIe, supports Class D (100 MHz)
– Level III, supports Class E (250 MHz)
– Level IIIe, supports Class EA (500 MHz)
– Level IV, supports Class F (600 MHz)
– Level V, supports Class FA (1,000 MHz)
• Status
– Draft, publication Q2 2014? – Work can begin on 2 GHz field testing once published
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ANSI/TIA-1152
• Defines field tester accuracy for ANSI/TIA-568-C.2 – Level IIe, supports Category 5e (100 MHz)
– Level III, supports Category 6 (250 MHz)
– Level IIIe, supports Category 6A (500 MHz)
• Status
– Published September 2009
– Opened for review at TIA meeting in Portland (June 2013)
•Editor: Fluke Networks
– Work has begun on supporting 2 GHz field testing
– Other measurements to be considered
• Resistance, Resistance Unbalance
– Possible new link definition(s)
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Resistance Unbalance
• Specified in IEEE 802.3af and IEEE 802.3at for thesuccessful transmission of Power over Ethernet
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Resistance Unbalance
• Difference in DC Resistance between conductors of thesame pair
1.87 Ω
1.85 Ω
Resistance = 3.7 Ω
Resistance Unbalance = 0.02 Ω
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Resistance Unbalance
• ISO/IEC 11801:2010 – 0.15 Ω or 3.0% for the Permanent Link (Greater of the two)
– 0.20 Ω or 3.0% for the Channel (Greater of the two)
– Not a requirement in IEC 61935-1 field testing standard….yet
• ANSI/TIA-568-C.2
– 0.20 Ω or 3.0% for the Channel (Greater of the two)
– Not a requirement in ANSI/TIA-1152 field testing standard…yet
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Copper Cladded Aluminum Cable
• Limited data from the field suggests this measurementcould be used to detect the presence of such cable
• CCA cable is not permitted in either TIA or ISO
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ANSI/TIA-568-C.2-1
• Category 8 – Support proposed for 40GBASE-T
– Supported Channel length now 30 m
• Status
– Working on laboratory fixtures to support 2 GHz testing
– Need round robin testing between labs to see if there is good
correlation of measurements
– Test plug performance to be decided
• No fixture available to measure test plugs to 2 GHz
– Field testers
• Baseline accuracy demonstrated
• No Channel measurement accuracy demonstrated
• No Perm. Link accuracy demonstrated
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ANSI/TIA-568-C.2-1
• Baseline accuracy – Accuracy without adapters
Adapter development is the real challenge here
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New FIELD copper measurements
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Balance
• Balance is critical for successful transmission• Reduces emissions
• Mitigates external noise sources
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Balance
• Balance is critical for successful transmission• Reduces emissions
• Mitigates external noise sources
8/13/2019 1.3 Field Testing Update
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Balance
• Defined in ANSI/TIA-568-C.2 – Channel limits only for TCL and ELTCTL
– Not a requirement in ANSI/TIA-1152 field testing
• Defined in ISO/IEC 11801:2010
– Channel limits for only TCL and ELTCTL
– Not a requirement in IEC 61935-1 Ed.4 (draft) field testing
• Industrial Ethernet group very interested
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TCL (Transverse Conversion Loss)
• Transverse Conversion Loss is the ratio (in dB) of a common-modevoltage measured on a wire pair relative to a differential-mode
voltage applied to the same end of the pair. The TCL value shows
you how well the impedances of the pair’s conductors are
balanced.
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TCL (Transverse Conversion Loss)
• A high TCL value means that the impedances of the conductorsrelative to ground are almost equal.
High TCL values correspond
to better noise immunity and
lower emissions.
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TCTL (Transverse Conversion Transfer Loss)
• Transverse Conversion Transfer Loss is the ratio (in dB) of acommon-mode voltage measured at the far end of a wire pair
relative to a differential-mode voltage applied to the near end of
the same pair.
• TCTL values improve with longer links
• We actually use Equal Level Transverse Conversion Loss (ELTCTL)
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ELTCTL (Equal Level Transverse Conversion Transfer Loss)
• Subtracting the ef fects of insertion loss normalizes the results forlength and produces ELTCTL values, which are not dependent on
length.
Because ELTCTL does not
depend on length, it is usedinstead of TCTL to evaluate cable
performance.
High ELTCTL values correspond
to better noise immunity and lower
emissions.
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Shield integrity
• ALL wire mappers would think the shield was connected• Grounding of two racks makes this happen
• Poor shielded terminations can result in poor Alien Crosstalk
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Shield integrity
• An incorrectly terminated shield can adversely affecttransmission properties such as Alien Crosstalk
The data below was taken from a data center where the shield was terminated incorrectly
The traditional Wire Map passed the shield shield
Worse
Better
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Shield Integrity
• New Wire Map approach – Use a Time Domain Reflectometer test to see if the shield is
truly connected by applying a differential signal between the
shield and all four pairs
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Shield integrity
• Even when the two connectors are grounded together
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Shield integrity
• Traditional Wire Mappers will show this connected
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Modified Single Connector Permanent Link
• IP camera and Wireless Access Point links are oftenterminated with an RJ45 plug
• Standards participants looking to define this link
definition which is already found in BICSI but no testguidelines are given
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Modified Single Connector Permanent Link
• Recommended method at this time is to use aPermanent Link Adapter at one end and a Channel
Adapter at the other
• Use Permanent Link
test limits
• Remote RJ45 plug excludedfrom measurement
Perm. Link Adapter
Channel Adapter
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Modified Single Connector Permanent Link
• Using time domain techniques, it is possible to see if theRJ45 plug is “bad” but there is no standard to support
this……
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Fiber Standards Update
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ISO/IEC 14763-3 (2006)
• This standard us under review• Two methods to measuring a Permanent Link
– 1 Jumper reference
• Accepted as the measurement with the least uncertainty
– 3 Jumper reference• Required for legacy test equipment that has fixed input ports
• Users often end up with negative loss readings
• Negative loss readings rejected for warranty application
• Measurement uncertainty in the field is unacceptable – Too many negative loss readings!
• There was a proposal to a variation of the 3 Jumper Reference but it
was rejected over concerns of a change in reference planes
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ANSI/TIA-526-14-B
• Title: Optical Power Loss Measurements of InstalledMultimode Fiber Cable Plant
• Localized changes being made to only require Encircled
Flux for OM3/OM4 installations
– Was talk of bring back Coupled Power Ratio (Rejected)
– Coupled Power Ratio has a measurement uncertainty of 40%
– Use of expensive and difficult to get hold of launch
conditioners driving this change
• Still recommends Encircled Flux compliant sources for
other multimode fibre types
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ANSI/TIA-526-14-B
• No option to use a Vertical Cavity Surface Emitting Laser(VCSEL) as a source, previous 526-14-A did allow them
• VCSELs have a spectral width ≈ 0.47 nm
• Measurement uncertainty associated with VCSELs is
unacceptable with todays low loss components
• Cabling vendors rejecting these results too
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ANSI/TIA-526-14-C (In progress)
• ANSI/TIA-526-14-B = Adoption of IEC 61280• ANSI/TIA-526-14-C = Adaptation of IEC 61280
• ANSI/TIA-526-14-C – Make 50 µm 850 nm normative for Encircled Flux
– All other cases informative for Encircled Flux
– Proposal for HOML for informative cases accepted
• HOML = Higher Order Modal Loss• Experiments by FNET proved concept
• Produces a field verification method that anyone could do
• Not a substitute for Encircled Flux – 20% confidence factor
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HOML Procedure
32
STEP 1: HOML with TRC, 50 µm or 62.5 µm versions
STEP 2: HOML with simple 5-turn mandrel, 50 µm or 62.5 µm versions
Dual wavelength
light source
50 µm or 62.5 µm TRC P0
Dual wavelength
light source
50 µm or 62.5 µm TRC
5 Turn, 17 mm/22 mm
P1
HOML is the difference in power comparing 0 turns with 5 turns (P0-P1)
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TIA-TSB-4979
• Title: Practical Considerations for Implementation ofMultimode Launch Conditions in the Field
• Gives two options on being Encircled Flux compliant
– Use a launch conditioner
– User a test cord tuned to an Encircled Flux compliant source
• Encircled Flux compliant sources reduce measurement
uncertainty due to launch conditions from 40%* to 10%
* Some experts are suggesting this is closer to 60% based on their testing
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TIA-TSB-4979
• Method 1: Launch Conditioner
• Makes any LED source Encircled Flux compliant
• User complain of bulkiness
• Cost concerns
• Can be difficult to get hold of
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TIA-TSB-4979
• Method 2: Matched source and test reference cord
• Tester vendor specific
• More “elegant”
• Significantly cheaper
EFEF
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Is EF needed?
• Yes• Data Centres are multi-connector environments
• The use of low loss components is required
• If the consultant or cabling vendor specifies a loss
budget (limit) based on these numbers, you may not
achieve it with a non EF solution
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BICSI News
• Available online
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Questions?
Thank you for your time