By: Joseph D. Cornwall, CTS-D
Technology Evangelist — C2G
Technical lingo is a kind of shorthand that's used to express concepts common to that specific topic or area of study. Technical lingo is important because it provides a very precise or unique "shorthand" description of a device, effect or concept. Unfortunately, if you aren't comfortable and familiar with the lingo of a topic it can be a tall hurdle to communicate efficiently with folks who consider the jargon of their field to be "self-explanatory." In this series of articles we'll lift the veils of misunderstanding from the lingo of the A/V industry.
The concept of Category cables was first set forth by the Electronic Industries Alliance (EIA) and is now maintained by the Telecommunications Industry Association (TIA). In 1991 the TIA/EIA-568-A standard was released (now revised to TIA/EIA-568-C) in an effort to define standards for telecommunications installations. In particular, the standard worked to define elements of balanced twisted pair cabling, fiber optic cabling and coaxial cabling, along with the associated connectors. The Cat cables discussed here are of the unshielded twisted pair (UTP) variety.
You can't be in the A/V or IT industry and not have heard of Cat5e and Cat6 cables. The Cat, as you might know, is short for "Category." The term "Category" refers to the different levels of performance in signal bandwidth, attenuation and crosstalk associated with each cable's design.
Category 1 cables are a 2-pair copper UTP designed for POTS (plain old telephone systems). Capable of up to 1MHz bandwidth, Cat1 cables were once the most common telecommunications cables and were found in almost every home and office. Cat 1, however, isn't capable of carrying data due to its very constricted bandwidth.
Category 2 cables upped the game by doubling the conductor count to 4 twisted pairs. This design also increased bandwidth to a blistering 4Mbps, enough for teletype and fax communications! It's important to note that both Cat1 and Cat2 are name variations of Level 1 and Level 2 cables, which were originally defined by the low voltage distribution company Anixter International. Neither of these cables is defined in the TIA 568-C standard.
Category 3 cabling commonly known as Cat3 or "station wire," is an unshielded twisted pair cable designed to carry data up to 10 Mbps. It was used in the early 1990's for computer networking, in particular in a system known as "Token Ring." Cat3 is defined in the TIA 568-C standard and is still in use as a telephone wiring.
Category 4 cabling improved on Cat3 and offered up to 16 Mbps of bandwidth and was commonly used in both Token Ring and early 10Base-T networks. Cat4 is no longer recognized in TIA 568-C.
Category 5 cables are the most ubiquitous UTP networking cables on the planet. Category 5 enhanced cables are known as Cat5e and offer better crosstalk capability than the original Cat5, but deliver the same 100MHz bandwidth. Cat5e is used in structured cabling for computer networks such as 10Base-T, 100Base-TX (Fast Ethernet), and 1000Base-T (Gigabit Ethernet). Cat5e is also used for many A/V and telephony applications.
Category 6 (Cat6) is a standardized cable for Gigabit Ethernet and other network physical layers that is backward compatible with the Category 5/5e and Category 3 cable standards. Cat6 has much higher specifications for both crosstalk and system noise, and provides up to 250MHz bandwidth. It's typically used in 1000Base-T (Gigabit Ethernet) and 10GBase-T (10-Gigabit Ethernet). Cat6a is an "augmented" Category 6 cable that offers up to 500MHz bandwidth. Cat6 is important in digital video applications such as HDBaseT also.
At this time, there is no such thing as a TIA-568 Category 7 cable. There is an ISO/IEC (International Standards Organization/ International Electrotechnical Commission) European standard (ISO/IEC 11801) that defines a Class F cable with 600MHz bandwidth, and even a Class F augmented standard for up to 1000MHz bandwidth. Neither of these are recognized by TIA, but efforts are in place to define these very high standards.
As Paul Harvey would say; "Now you know the rest of the story."
This white paper is for informational purposes only and is subject to change without notice. C2G makes no guarantees, either expressed or implied, concerning the accuracy, completeness or reliability of the information found in this document.