Cables

B-4

B

Cable Testing for Existing Category 5 Cable

Installed Category 5 cabling must pass tests for Atte nuation, 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.

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 numb er of connectors used in the link.
3. Reconnect some of the co nnectors in the link.
Fiber Standards
The current TIA (Telecommunications Industry Association) 568-A specification on
optical fiber cabling consists of one recognized cable type for horizontal s ubsystems
and two cable types for backbone subsystem s.
Horizontal 62.5/125 micron multimode (two fibers per outlet).
Backbone 62.5/125 micron multimode or single-mod e.
TIA 568-B will allow the use of 50/125 micron multimode optical fiber in both the
horizontal and backbone in addition to the types listed above. All optical fiber
components and installation practices must meet applicable building and sa fety
codes.