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The Specification of Field
Test Requirements for Fiber Optic Cabling System
A. General Requirements
1. Every fiber optic cabling link in the
installation shall be tested in accordance with the field
test specifications defined by the Telecommunications Industry
Association (TIA) standard ANSI/TIA/EIA-568-B (or by the appropriate
network application standard(s) whichever is more demanding.
See Section B.
2. ANSI/TIA/EIA-568-B, defines the passive cabling
network, to include cable, connectors, and splices (if present),
between two optical fiber patch panels (connecting hardware).
A typical horizontal link segment is from the telecommunications
outlet/connector to the horizontal crossconnect. This TIA
document describes three typical backbone link segments:
(1) main crossconnect to intermediate cross-connect,
(2) main cross-connect to horizontal cross-connect,
(3) intermediate cross-connect to horizontal
cross-connect. The test
shall include the representative connector performance at
the
connecting hardware associated with the mating of patch cords.
The test does not, however, include the performance of the
connector at the interface with the test equipment.
3. 100% of the installed cabling links must be tested
and must pass the requirements of the standards mentioned
in A.1 above and as further detailed in Section B. Any failing
link must be diagnosed and corrected. The corrective action
shall be followed with a new test to prove that the corrected
link meets the performance requirements. The final and passing
result of the tests for all links shall be provided in the
test results documentation in accordance with Section 0 below
.
4. Trained technicians who have successfully attended
an appropriate training program and have obtained a certificate
as proof thereof shall execute the tests. These certificates
may have been issued by any of the following organizations
or an equivalent organization:
the manufacturer of the fiber optic cable and/or the fiber optic connectors
the manufacturer of the test equipment used for the field
certification
training organizations
authorized by BiCSi (Building Industry Consulting Services
International with headquarters in Tampa, Florida) or by
the ACP (Association of Cabling Professionals Cabling Business
Institute located in Dallas, Texas.
5. Field test instruments for multimode fiber cabling
shall meet the requirements of ANSI/TIA/EIA- 526-14A. The
light source shall meet the launch requirements of ANSI/EIA/TIA-455-50B,
Method A. This launch condition can be achieved either within
the field test equipment or by use of an external mandrel
wrap (as described in clause 11 of ANSI/TIA/EIA-568-B.1)
with a Category 1 light source.
Field test instruments for singlemode fiber cabling shall
meet the requirements of ANSI/EIA/TIA-526-7.
6. The tester shall be within the calibration period
recommended by the vendor in order to achieve the vendor-specified
measurement accuracy.
7. The fiber optic launch cables and adapters must
be of high quality and the cables shall not show excessive
wear resulting from repetitive coiling and storing of the
tester interface adapters.
8. The Pass or Fail condition for the link-under-test
is determined by the results of the required individual
tests (detailed in Section I.B).Field Test Specifications
for Fiber Optic Installations Page 2 of 4
9. A Pass or Fail result for each parameter is determined
by comparing the measured values with the specified test
limits for that parameter.
10. Optional Requirements:
11. A representative of the end-user shall be invited
to witness field testing. The representative shall be notified
of the start date of the testing phase 5 business days before
testing commences.
12. A representative of the end-user will select
a random sample of 5% of the installed links. The representative
(or his authorized delegate) shall test these randomly selected
links and the results are to be stored in accordance with
the prescriptions in Section 0. The results obtained shall
be compared to the data provided by the installation contractor.
If more than 2% of the sample results differ in terms of
the pass/fail determination, the installation contractor
under supervision of the end-user representative shall repeat
100% testing and the cost shall be borne by the installation
contractor.
B. Performance Test Parameters
1. ANSI/TIA/EIA standard 568-B prescribes that the single
performance parameter for field testing of fiber optic links
is link attenuation (alternative and equivalent term: insertion
loss), when installing components compliant with this standard.
2.The link attenuation shall be calculated by the
following formulas specified in ANSI/TIA/EIAstandard 568-B
Link Attenuation = Cable_Attn + Connector_Attn + Splice_Attn
Cable_Attn (dB) = Attenuation_Coefficient (dB/km) * Length
(Km)
The values for the Attenuation_Coefficient are listed in
the table below:
| Type of Optical Fiber(dB/km) |
Wavelength (nm) |
Attenuation_Coefficient(dB/km) |
| Multimode 62.5/125 ��m |
850 |
3.5 |
| |
1300 |
1.5 |
| Multimode 50/125 ��m |
850 |
3.5 |
| |
1300 |
1.5 |
| Single-mode(Inside plant) |
1310 |
1.0 |
| |
1550 |
1.0 |
| Single-mode (Outside plant) |
1310 |
0.5 |
| |
1550 |
0.5 |
Connector_Attn (dB) = number_of_connector_pairs *
connector_loss (dB)
Maximum allowable connector_loss = 0.75 dB
Splice_Attn (dB) = number of splices (S) * splice_loss
(dB)
Maximum allowable splice_loss = 0.3 dB
Link attenuation does not include any active devices or
passive devices other than cable, connectors, and splices,
i.e. link attenuation does not include such devices as
optical bypass switches, couplers, repeaters, or optical
amplifiers.Test equipment that measures the link length
and automatically calculates the link loss based on the
above formulas is preferred. Field Test Specifications
for Fiber Optic Installations Page 3 of 4
3. The above link test limits attenuation are based
on the use of the One Reference Jumper Method specified
by ANSI/TIA/EIA-526-14A, Method B and ANSI/TIA/EIA-526-7,
Method A.1; or the equivalent method. The user shall follow
the procedures established by these standards or application
notes to accurately conduct performance testing.
4. The horizontal link (multimode): acceptable
link attenuation for a multimode horizontal optical fiber
cabling system is based on the maximum 90 m (295 ft) distance.
The horizontal optical fiber cabling link segments need
to be tested at only one (1) wavelength. Because of the
short length of cabling [90 m (295 ft) or less], attenuation
deltas due to wavelength are insignificant. The horizontal
link should be tested at 850 nm or 1300 nm in one direction
in accordance with ANSI/EIA/TIA-526-14A, Method B, One
Reference Jumper method. The horizontal link may be tested
using a fixed upper limit for attenuation of 2.0 dB. This
value is based on the loss of two (2) connector pairs,
one (1) pair at the telecommunications outlet/connector
and one (1) pair at the horizontal cross-connect, plus
90 m (295 ft) of optical fiber cable.
5. The backbone link (multimode) shall be tested
in one direction at both operating wavelengths to account
for attenuation deltas associated with wavelength.
6. Multimode backbone links shall be tested at
850 nm and 1300 nm in accordance with ANSI/EIA/TIA-526-14A.
Because backbone length and the potential number of splices
vary depending upon site conditions, the link attenuation
equation (Section B.2) shall be used to determine limit
(acceptance) values.
7. Singlemode backbone links shall be tested at
1310 nm and 1550 nm in accordance with ANSI/TIA/EIA-526-7,
Method A.1, One Reference Jumper or the equivalent method.
All singlemode links shall be certified with test tools
using laser light sources at 1310 nm and 1550 nm (See
Note below).
NOTE:a) Link attenuation has been based upon the use of
a light source categorized by a Coupled Power Ratio (CPR)
of Category 2, Underfilled, per Annex B of ANSI/EIA/TIA-526-14A.
The use of a light source categorized as Category 1, Overfilled,
may provide results higher than the 2.0 dB limit. A field
test tool based on LED (light emitting diode) light sources
is a Category 1 device and typically yields high attenuation
results.b) Links destined to be used with network applications
that use laser light sources (underfilled launch conditions)
shall be tested with test equipment based on laser light
sources. This rule should be followed for cabling systems
to support Gigabit Ethernet. Gigabit Ethernet only specifies
laser light sources.
For Gigabit Ethernet compliant certification (IEEE std
802.3z application), use test equipment which uses a VCSEL
(Vertical cavity surface emitting laser) at 850 nm (compliant
with 1000BASE-SX) and an FP laser at 1310 nm (compliant
with 1000BASELX).
8. Optional requirement:
Each fiber optical link terminated with an optical adapter
system which does not impose a transmission direction
because the adapters are not or cannot be ganged should
be tested and documented in both direction since the direction
of the signal transmission cannot be predicted at the
time of installation.
C. Test Result Documentation
1. The test result information for each
link shall be recorded in the memory of the field tester
upon completion of the test.
2. The test result records saved by the tester
shall be transferred into a Windows?-based database utility
that allows for the maintenance, inspection and archiving
of these test records.
A guarantee must be made that these results are transferred
to the PC unaltered, i.e., "as saved in the tester"
at the end of each test. The popular 'csv' format (comma
separated value format) does not provide adequate protection
and shall not be acceptable.
3. The database for the completed job - including
twisted-pair copper cabling links if applicable - shall
be stored and delivered on CD-ROM; this CD-ROM shall include
the software tools required to view, inspect, and print
any selection of test reports.
4. A paper copy of the test results shall be provided
that lists all the links that have been tested with the
following summary information
a) The identification
of the link in accordance with the naming
convention defined in the overall system documentation
b) The overall Pass/Fail
evaluation of the link-under-test including
the Attenuation worst case margin (margin is defined as
the
difference between the measured value and the test limit
value).
c) The date and time
the test results were saved in the memory of
the tester
5. General Information to be provided in the electronic
data base containing the test result information for each
link:
a) The identification
of the customer site as specified by the end-
user
b) The overall Pass/Fail
evaluation of the link-under-test
c) The name of the
standard selected to execute the stored test
results
d) The cable type
and the value of the 'index of refraction' used for
length calculations
e) The date and time
the test results were saved in the memory of
the tester
f) The brand name,
model and serial number of the tester
g) The revision of
the tester software and the revision of the test
standards database in the tester.
6. The detailed test results data to be provided
in the electronic database for each tested optical fiber
must contain the following information
a) The identification
of the link/fiber in accordance with the naming
convention defined in the overall system documentation
b) The insertion loss
(attenuation) measured at each wavelength,
the test limit calculated for the corresponding wavelength
and
the margin (difference between the measured attenuation
and
the test limit value).
c) The link length
shall be reported for each optical fiber for which
the test limit was calculated based on the formulas in
section
B.2.
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