UTP Cabling
The '568-A specifications on unshielded twisted-pair cabling supersede TSB-36 and TSB40-A. The three categories of transmission performance specified for cables, connecting hardware and links are:
Transmission characteristics are specified up to 100 MHz.
Transmission characteristics are specified up to 20 MHz.
Transmission characteristics are specified up to 16 MHz.
UTP categories 1 and 2 are not specified.
Components and installation practices are subject to all applicable building and safety codes that may be in effect.
Note: Category 3 requirements are consistent with the UTP specifications for horizontal cable and connecting hardware in the original edition of '568.
Horizontal UTP Cable:
 Solid 4-pair 0.5 mm (24 AWG) specified [0.63 mm (22 AWG) solid also allowed]. Overall shield is optional.
- Performance marking should be provided to show the applicable performance category. These markings do not replace safety markings.
UTP Telecommunications Outlet/Connector:
- 8-position modular jack per IEC 603-7 (all 4 pairs must be connected)
 Pin/pair assignment: T568A (US federal government publication FIPS PUB 174 recognizes designation T568A only).
- Optional assignment to accommodate certain systems: T568B
- Durability rating 750 mating cycles minimum.
Backbone UTP Cable: 
- Performance markings should be provided to show the applicable performance category. These markings do not replace safety markings.
- Services with incompatible signal levels should be partitioned into separate binder groups.
- Transmission requirements are equivalent to horizontal cables except that NEXT loss performance is based on power-sum rather than worst-pair characterization to allow for multiple disturbing signals in the same sheath.
- Note: Tip conductors have colored insulation that corresponds to that of the binder group. Ring conductors have colored insulation that corresponds to that of the pair.
- Backbone UTP cables consist of solid 0.5 mm (24 AWG) cables that contain more than four pairs (typically multiples of 25-pairs are used). An overall shield is optional.
UTP Connecting Hardware:
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- Specifications cover all types of connectors used in the cabling system including the telecommunications outlet/connector.
- Does not cover work area adapters, baluns, protection, MAUs, filters or other application-specific devices.
- Temperature range - 10°C (14°F) to 60°C (140°F).
- Outlets shall be securely mounted. Outlet boxes with unterminated cables must be covered and marked.
- Transmission requirements are much more severe than cable of a corresponding category. (See graph)
- Performance markings should be provided to show the applicable transmission category and should be visible during installation (for example CAT 5) in addition to safety markings.
- Installed connectors shall be protected from physical damage and moisture.
Connector Terminations:
- Pair twists shall be maintained as close as possible to the point of termination.
- Untwisting shall not exceed 25 mm (1.0 in.) for category 4 links and 13 mm (0.5 in.) for category 5 links.
- Connecting hardware shall be installed to provide well-organized installation with cable management and in accordance with manufacturers guidelines.
- Strip back only as much jacket as is required to terminate individual pairs.
UTP Link Performance and Marking:
- Link category marking should be clearly visible on both ends (component markings are not sufficient).
- Labeling, markings and color-coding shall be provided in accordance with ANSI/TIA/EIA-606.
- Guidelines on shared sheaths are provided in an informative annex.
- The horizontal link performance annex is provided for reference purposes only. Conformance is still governed by requirements on components and installation practices.
UTP Patch Cords and Cross-connect Jumpers:
Patch cords must use stranded cable for adequate flex-life.
Must meet minimum performance requirements for horizontal cable except that 20 percent more attenuation is allowed for stranded cables.
Color Codes for Stranded 100 Ohm UTP Patch Cord:
Option 1:
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Option 2:
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Note: Because of their identical pair groupings, patch cords terminated with either T568A or T568B pair assignments may be used interchangeably, provided that both ends are terminated with the same pin/pair scheme.
- Color-code for cross-connect jumpers: One conductor white, the other a visibly distinct color such as red or blue.
- Insulated O.D. of stranded wires should be 0.8 mm (0.032 in.) to 1 mm (0.039 in.) to fit into a modular plug.
- Performance markings should be provided to show the applicable transmission category in addition to safety markings.
- Performance specifications for plug cord assemblies are under study.
Cabling Practices:
- To avoid stretching, pulling tension should not exceed 110N (25 1bf) for 4-pair cables.
- Installed bend radii in spaces with UTP terminations shall not exceed:
- 4 times the cable diameter for horizontal UTP cables.
- 10 times the cable diameter for multi-pair backbone UTP cables.
- Avoid cable stress, as caused by:
- cable twist during pulling or installation
- tension caused by suspended cable runs
- tightly cinched cable ties
UTP Installation Practices:
- Horizontal cables should be used with connecting hardware and patch cords (or jumpers) of the same performance category or higher.
Important Note:
- Installed UTP cabling shall be classified by the least performing component in the link.
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