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



Objectives for this session

• Copper field standards update

• Look at new copper field measurements

• Fiber field standards update



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



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)



Resistance Unbalance

• Specified in IEEE 802.3af and IEEE 802.3at for thesuccessful transmission of Power over Ethernet




• Difference in DC Resistance between conductors of thesame pair

1.87 Ω

1.85 Ω

Resistance = 3.7 Ω

Resistance Unbalance = 0.02 Ω




• 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



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



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



ANSI/TIA-568-C.2-1

• Baseline accuracy – Accuracy without adapters

Adapter development is the real challenge here



New FIELD copper measurements



Balance

• Balance is critical for successful transmission• Reduces emissions

• Mitigates external noise sources



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



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.



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.



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)



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.



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



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



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



Shield integrity

• Even when the two connectors are grounded together



Shield integrity

• Traditional Wire Mappers will show this connected



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




• 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




• Using time domain techniques, it is possible to see if theRJ45 plug is “bad” but there is no standard to support

this……



Fiber Standards Update



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



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



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



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



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)



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



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



TIA-TSB-4979

• Method 2: Matched source and test reference cord

• Tester vendor specific

• More “elegant”

• Significantly cheaper

EFEF



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



BICSI News

• Available online



Questions?

Thank you for your time

1.3 field testing update

Documents