C
ABLES

B-4

1000BASE-T Cable Requirements
All Category 5 UTP cables that are used for 100BASE-TX
connections should also work for 1000BASE-T, providing that all
four wire pairs are connected. However, it is recommended that for
all critical connections, or any new cable installations, Category 5e
(enhanced Category 5) cable should be used. The Category 5e
specification includes test parameters that are only recommendations
for Category 5. Therefore, the fir st step in preparing existing
Category 5 cabling for running 1000BASE-T is a simp le test of the
cable installation to be sure that it complies with the IEEE 802.3ab
standards.

Cable Testing for Existing Category 5 Cable

Installed Category 5 cabling must pass tests for Attenu ation,
Near-End Crosstalk (NEXT), and Far-End Crosstalk (F EXT). 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.

Adjusting Existing Category 5 Cabling

If your existing Category 5 installation does not meet one of the te st
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 cables.
2. Reduce the number of connectors used in the link.
3. Reconnect some of the connectors in the link.