Category6 cable (Cat6) is a standardized twisted pair cable for Ethernet and other network physical layers that is backward compatible with the Category 5/5e and Category 3 cable standards.

Cat6 must meet more stringent specifications for crosstalk and system noise than Cat5 and Cat5e. The cable standard specifies performance of up to 250MHz, compared to 100MHz for Cat5 and Cat5e.

Whereas Category6 cable has a reduced maximum length of when used for 10GBASE-T, Category6A cable is specified for 500MHz and has improved alien crosstalk characteristics, allowing 10GBASE-T to be run for the same maximum distance as previous Ethernet over twisted pair variants.

History

Cat6, an unshielded twisted-pair (UTP) design, emerged as an advancement of the UTP Cat5e and was formalised in 2001. The design of Cat6 required more stringent precision in manufacturing, which enabled reduced noise and crosstalk, thereby improving performance. The Telecommunications Industry Association (TIA) published Cat6 in June 2002.

Description

Cat6 cable can be identified by the printing on the side of the cable sheath. Cable types, connector types and cabling topologies are defined by ANSI/TIA-568.

Cat6 patch cables are normally terminated in 8P8C modular connectors, using either T568A or T568B pin assignments; performance is comparable provided both ends of a cable are terminated identically.

If Cat-6–rated patch cables, jacks and connectors are not used with Cat6 wiring, overall performance is degraded and may not meet Cat6 performance specifications.

The Cat6 specification requires conductors to be pure copper. The industry has seen a rise in non-compliant or counterfeit cables, especially of the copper-clad aluminium wire (CCA) variety. This has exposed the manufacturers or installers of such fake cable to legal liabilities. The diameter of the wires in Cat 6 cables ranges from 22 to 26 AWG.

Category 6A

The standard for Category6A (augmented Category 6) is ANSI/TIA-568.2-D (replaces 568-C.2), defined by TIA for enhanced performance standards for twisted pair cable systems. It was defined in 2009. Cat6A performance is defined for frequencies up to 500MHz—twice that of Cat6. Cat6A also has an improved alien crosstalk specification as compared to Cat6, which picks up high levels of alien noise at high frequencies.

The global cabling standard ISO/IEC 11801 has been extended by the addition of amendment 2. This amendment defines new specifications for Cat6A components and Class EA permanent links. These new global Cat6A/ClassEA specifications require a new generation of connecting hardware offering far superior performance compared to the existing products that are based on the American TIA standard. The most important point is a performance difference between ISO/IEC and EIA/TIA component specifications for the NEXT transmission parameter. At a frequency of 500MHz, an ISO/IEC Cat6A connector performs 3dB better than a Cat6A connector that conforms with the EIA/TIA specification (3dB equals 50% reduction of near-end crosstalk noise signal power; see half-power point).

Confusion therefore arises because of the naming conventions and performance benchmarks laid down by the International ISO/IEC and American TIA/EIA standards, which in turn are different from the regional European standard, EN 50173–1. In general, the ISO standard for Cat6A is the most stringent, followed by the European standard, and the American one (1 on 1 matching capability).

Category 6e

Cat6e is not a recognized standard and has no agreed meaning. After the ratification of Category6, manufacturers began offering cabling systems and solutions labeled as . This is a marketing claim from manufacturers and typically refers to a claim of headroom performance above the defined TIA Category 6 standard. The name resembles the name of the (legitimate) Category 5e standard.

Maximum length

When used for 10/100/1000BASE-T, the maximum allowed length of a Cat6 cable is . This consists of permanent link, which is typically solid horizontal cabling between two connectors, often the patch panel and the wall jack, plus total of stranded patch cordage. Manufacturers have begun offering claims of supporting distances beyond which would fall outside of the TIA 568–2.D standard.

Installation requirements

Category6 and 6A cable must be properly installed and terminated to meet specifications. The cable must not be kinked or bent too tightly; the bend radius should be larger than four times the outer diameter of the cable. The wire pairs must not be untwisted, and the outer jacket must not be stripped back more than .

Cable shielding may be required in order to avoid data corruption in high electromagnetic interference (EMI) environments. Shielding is typically maintained from one cable end to the other using a drain wire that runs through the cable alongside the twisted pairs. The shield's electrical connection to the chassis on each end is made through the jacks. The requirement for ground connections at both cable ends creates the possibility of creating a ground loop. This undesirable situation may compel currents to flow in the network cable shield and these currents may, in turn, induce detrimental noise in the signal being carried by the cable.

References

External links

• Information on cable construction and alien crosstalk mitigation.

• Information on TIA TSB-155 37m versus IEEE 55m limitations.