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Page 231
LGB5028A User‘s Manual
Appendix C: Cables
Table C-2. 1000BASE-T MDI and MDI-X port pinouts.
Pin MDI Signal Name MDI-X Signal Name
1 Bidirectional Pair A plus (BI_DA+) Bidirectional Pair B plus (BI_DB+)
2 Bidirectional Pair A minus (BI_DA-) Bidirectional Pair B minus (BI_DB-)
3 Bidirectional Pair B plus (BI_DB+) Bidirectional Pair A plus (BI_DA+)
4 Bidirectional Pair C plus (BI_DC+) Bidirectional Pair D plus (BI_DD+)
5 Bidirectional Pair C minus (BI_DC-) Bidirectional Pair D minus (BI_DD-)
6 Bidirectional Pair B minus (BI_DB-) Bidirectional Pair A minus (BI_DA-)
7 Bidirectional Pair D plus (BI_DD+) Bidirectional Pair C plus (BI_DC+)
8 Bidirectional Pair D minus (BI_DD-) Bidirectional Pair C minus (BI_DC-)
C.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.
C.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
measures that can be applied to try to 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.
C.8 Fiber Standards
The International Telecommunication Union (ITU-T) has standardized various fiber types for data networks. These are summarized
in Table C-3.
Table C-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 wavelength-division multiplexing (WDM)
transmission across wavelengths form 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 1500- to 1600-nm band.
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-divison
multiplexing (DWDM) operation in the region from 1500 to 1600 nm.
