B-4
Cables
B
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 that when testing your cable installation, be sure to include all patch cables
between switches and end devices.
Cable Testing for Category 6 and 6a Cable
Installed Category 6 cabling must pass tests specified in the ANSI/TIA-TSB-155 and
ISO/IEC 24750 standards. Category 6a cables must also pass test parameters
specified in the ANSI/TIA/EIA-568-B.2-10 standard. Methods of mitigating of alien
crosstalk in Category 6 and 6a cable is covered in ANSI/TIA-TSB-155 and ISO/IEC
TR24750.
Note that when testing your cable installation, be sure to include all patch cables
between switches and end devices.
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 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.
5 Bi-directional Data Three Minus (BI_DC-) Bi-directional Data Four Minus (BI_DD-)
6 Bi-directional Data Two Minus (BI_DB-) Bi-directional Data One Minus (BI_DA-)
7 Bi-directional Data Four Plus (BI_DD+) Bi-directional Data Three Plus (BI_DC+)
8 Bi-directional Data Four Minus (BI_DD-) Bi-directional Data Three Minus (BI_DC-)
Table B-2 1000BASE-T MDI and MDI-X Port Pinouts (Continued)
Pin MDI Signal Name MDI-X Signal Name
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