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Chapter 9: Cables
9.6 Cable Testing for Existing Category 5 Cable
Installed Category 5 cabling must pass tests for Attenuation, Near-End Crosstalk (NEXT), and Far-End Crosstalk (FEXT). This cable
testing information is specified in the ANSI/TIA/EIA-TSB-67 standard. Additionally, cables must also pass test parameters for
Return Loss and Equal-Level Far-End Crosstalk (ELFEXT). These tests are specified in the ANSI/TIA/EIA-TSB-95 Bulletin, “The
Additional Transmission Performance Guidelines for 100 Ohm 4-Pair Category 5 Cabling.”
NOTE: When testing your cable installation, be sure to include all patch cables between switches and end devices.
9.7 Adjusting Existing Category 5 Cabling to Run 1000BASE-T
If your existing Category 5 installation does not meet one of the test parameters for 1000BASE-T, there are basically three mea-
sures that can be applied to try and correct the problem:
1. Replace any Category 5 patch cables with high-performance Category 5e or Category 6 cables.
2. Reduce the number of connectors used in the link.
3. Reconnect some of the connectors in the link.
9.8 Fiber Standards
The International Telecommunication Union (ITU-T) has standardized various fiber types for data networks. These are summarized
in the following table.
Table 9-3. Fiber standards.
ITU-T Standard Description Application
G.651 Multimode Fiber
50/125-micron core
Short-reach connections in the 1300-nm or 850-nm band
G.652 Non-Dispersion-Shifted Fiber
Single-mode, 9/125-micron core
Longer spans and extended reach. Optimized for operation
in the 1310-nm band, but can also be used in the 1550-nm
band.
G.652.C Low Water Peak Non-Dispersion-Shifted Fiber
Single-mode, 9/125-micron core
Longer spans and extended reach. Optimized for wave-
length-division multiplexing (WDM) transmission across
wavelengths from 1285 to 1625 nm. The zero dispersion
wavelength is in the 1310-nm region.
G.653 Dispersion-Shifted Fiber
Single-mode, 9/125-micron core
Longer spans and extended reach. Optimized for operation
in the region from 1500 to 1600 nm.
G.654 1550-nm Loss-Minimized Fiber
Single-mode, 9/125-micron core
Extended long-haul applications. Optimized for high-power
transmission in the 1500 to 1600-nm region, with low loss in
the 1550-nm band.
G.655 Non-Zero Dispersion-Shifted Fiber
Single-mode, 9/125-micron core
Extended long-haul applications. Optimized for high-power
dense wavelength-division multiplexing (DWDM) operation
in the region from 1500 to 1600 nm.
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