What are the cat cable types

Though two cables may look identical, their supported data rates can be dramatically different.
Older UTP cables that were installed to support telephone systems may not even support
10Base-T Ethernet. The ANSI/TIA/EIA-568-B Standard helps consumers choose the right cable
(and components) for the right application. The Standard has been updated over the years and
currently defines four categories of UTP cable: Categories 3, 5, 5e, and 6. Note that Category
5 requirements have been moved to an addendum and are not officially recognized as an
approved cable for new installations. Here is a brief rundown of Categories past and present:
Category 1 (not defined by ANSI/TIA/EIA-568-B)
This type of cable usually supports frequencies
of less than 1MHz. Common applications include analog voice telephone systems. It
never existed in any version of the 568 Standard.
Category 2 (not defined by ANSI/TIA/EIA-568-B)
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 networks. Its requirements are based on the original, proprietary
IBM Cabling System. It never existed in any version of the 568 Standard.
Category 3 (recognized cable type in ANSI/TIA/EIA-568-B)
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 analog telephone systems. Its inclusion in the
568-B Standard is for voice applications.
Category 4 (not defined by ANSI/TIA/EIA-568-B)
Cable belonging to Category 4 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 it has been dropped
from ANSI/TIA/EIA-568-B.
Category 5 (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, PMD (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 specified by TSB-95 (TSB-95 was a Technical Service 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/EIA-568-B Standard, but for historical reference purposes,
Category 5 requirements, including those taken from TSB-95, are specified in
Appendix D of 568-B.1 and Appendix N of 568-B.2.
Category 5e (recognized cable type in ANSI/TIA/EIA-568-B)
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, i.e., 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/EIA-568-B.
Category 6 (recognized cable type in ANSI/TIA/EIA-568-B)
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 200MHz. 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, i.e., patch cords,
connectors, and cable.