Unshielded Twisted-pair has been used for many year for telephone systems, it is become common in the late 1980s with the advance of Ethernet over twisted-pair wiring and the 10Base-T standard. UTP is cost effective and simple to install, and its bandwidth capabilities are continually being improved. Media converters allow cost-effective conversion of signals from one cabling media type to another. The most common type converts signals runing over copper UTP cabling to fiber optic cabling. Fiber Ethernet converter also exist to support conversion of coax cable to UTP cable for fiber optic cabling.
UTP cabling typically has only one outer covering jacket that consist of come type of nonconducting material. This jacket cover one or more pair of wire that are twisted together. Unshielded twisted pair cable is most commonly comprised of 4 twisted pair of copper conductors, graded for bandwidth as “level” or “Categories”. A typical UTP cable consist of a jacket that surrounds four twisted pairs. Each wire is covered by an insulation material with good dielectric properties. For data cables, this means that in addition to being electrically nonconductive, it must have certain properties that allow good signal propagation.
Older UTP cables that were installed to support telephone systems may not even support 10Base-T Ethernet. The ANSI/TIA-538-C standard helps consumers choose the right cable for their applications.
This standard has been updated over the years and currently defined four categories of UTP cables: Categories 3, 5e, 6, 6A. So, even though two cables may look identical, their supported data rates can be dramatically different.
Category 1: This type of cable usually supports frequencies of less than 1 MHz. Common applications include analog voice telephone systems. It ware never included in any version of the 568 standard.
Category 2: This cable type supports frequencies of up to 4MHz. It’s not commonly installed, except in installations that use twisted-pair ARCnet and Apple LocalTalk netwokrs. Its requirements are based on the original, proprietary IBM cabling system specification. It was never included in any version of the 568 standard.
Category 3 (recognized cable type in ANSI/TIA-568-C): This type of cable supports data rates up to 16Mhz. This cable was the most common variety of UTP for a number of years starting in the late 1980s. Common applications include 4Mbps UTP Token Ring, 10Base-T Ethernet. 100Base-T4, and digital and analogy telephone systems. Its inclusion in the ANSI/TIA-568-C standard is for voice applications.
Category 4: Cat 4 UTP cable was designed to support frequencies of up to 20Mhz, specifically in response to a need for a UTP solution for 16Mbps Token Ring LANs. It was quickly replaced in the market when Category 5 was developed, as Category 5 gives five times the bandwidth with only a small increment in price. Category 4 was a recognized cable in the 568-A standard, but was dropped from ANSI/TIA-568-B and also does not appear in ANSI/TIA-568-C.
Category 5 (was included in ANSI/TIA/EIA-568-B for informative purposes only): Category 5 was the most common cable installed, until new installations began to use an enhanced version. It may still be the cable type most in use because it was the cable of choice during the huge infrastructure boom of the 1990s. It was designed to support frequencies of up to 100MHz.
Applications include
100Base-TX, FDDI over copper, 155Mbps ATM over UTP, and, thanks to sophisticated encoding techniques, 1000Base-T Ethernet. To support 1000Base-T applications, the installed cabling system had to pass performance tests speci-fied by TSB-95 (TSB-95 was a Telecommunications Systems Bulletin issued in support of ANSI/TIA/EIA-568-A, which defines additional test parameters). It is no longer a recognized cable type per the ANSI/TIA-568-C standard, but for historical reference purposes, Category 5 requirements, including those taken from TSB-95, are specified in ANSI/TIA-568-C.2.
Category 5 (was included in ANSI/TIA/EIA-568-B for informative purposes only): Category 5 was the most common cable installed, until new installations began to use an enhanced version. It may still be the cable type most in use because it was the cable of choice during the huge infrastructure boom of the 1990s. It was designed to support frequencies of up to 100MHz. Applications include 100Base-TX, FDDI over copper, 155Mbps ATM over UTP, and, thanks to sophisticated encoding techniques, 1000Base-T Ethernet. To support 1000Base-T applications, the installed cabling system had to pass performance tests speci-fied by TSB-95 (TSB-95 was a Telecommunications Systems Bulletin issued in support of ANSI/TIA/EIA-568-A, which defines additional test parameters). It is no longer a recognized cable type per the ANSI/TIA-568-C standard, but for historical reference purposes, Category 5 requirements, including those taken from TSB-95, are specified in ANSI/TIA-568-C.2.
Category 5e (recognized cable type in ANSI/TIA-568-C): Category 5e (enhanced Category 5) was introduced with the TIA/EIA-568-A-5 addendum of the cabling standard. Even though it has the same rated bandwidth as Category 5, that is, 100MHz, additional performance criteria and a tighter transmission test requirement make it more suitable for high-speed applications such as Gigabit Ethernet. Applications are the same as those for Category 5 cabling. It is now the minimum recognized cable category for data transmission in ANSI/TIA-568-C.
Category 6 (recognized cable type in ANSI/TIA-568-C): Category 6 cabling was officially recognized with the publication of an addition to ANSI/TIA/EIA-568-B in June 2002. In addition to more stringent performance requirements as compared to Category 5e, it extends the usable bandwidth to 250MHz. Its intended use is for Gigabit Ethernet and other future high-speed transmission rates.
Successful application of Category 6 cabling requires closely matched components in all parts of the transmission channel, that is, patch cords, connectors, and cable.
Category 6A or Augmented Category 6 (recognized cable type in ANSI/TIA-568-C): Category 6A cabling was officially recognized with the publication of ANSI/TIA/EIA-568-B.2-10 in February 2008. In addition to more stringent performance requirements as compared to Category 6, it extends the usable bandwidth to 500MHz. Its intended use is for 10 Gigabit Ethernet. Like Category 6, successful application of Category 6A cabling requires closely matched components in all parts of the transmission channel, that is, patch cords, connectors, and cable. The cabling standards are discussed inmore detail in Chapter 2. Additional information on copper media can be found in Chapter 7, “Copper Cable Media,” and Chapter 10, “Connectors.”
Category 7 (recognized cable type in ISO 11801): Category 7 is an ISO/IEC category suitable for transmission frequencies up to 1Ghz. Cat7 Ethernet cable is widely used in Europe and is gaining some popularity in the United States. It is not presently recognized in ANSI/TIA-568-C.
