cat standards categories

The standards categories

Category	Maximum data rate	Usual application
CAT 1 (de facto name, never a standard)	Up to 1 Mbps (1 MHz)	analog voice (POTS) Basic Rate Interface in ISDN Doorbell wiring
CAT 2(de facto name, never a standard)	4 Mbps	Mainly used in the IBM cabling system for Token Ring networks
CAT 3	16 Mbps	Voice (analog most popular implementation) 10BASE-T Ethernet
CAT 4	20 Mbps	Used in 16 Mbps Token Ring, otherwise not used much. Was only a standard briefly and never widely installed.
CAT 5	100 MHz	100 Mbps TPDDI 155 Mbps ATM No longer supported; replaced by 5E. 10/100BASE-T 4/16MBps Token Ring Analog Voice
CAT 5E	100 MHz	100 Mbps TPDDI 155 Mbps ATM Gigabit Ethernet Offers better near-end crosstalk than CAT 5
CAT 6	Up to 250 MHz	Minimum cabling for data centers in TIA-942. Quickly replacing category 5e.
CAT 6E	MHz  (field-tested to 500 MHz)	Support for 10 Gigabit Ethernet (10GBASE-T) May be either shielded (STP, ScTP, S/FTP) or unshielded (UTP) This standard published in Feb. 2008. Minimum for Data Centers in ISO data center standard.
CAT 7 (ISO Class F)	600 MHz 1.2 GHz in pairs with Siemon connector	Full-motion video Teleradiology Government and manufacturing environments Fully Shielded (S/FTP) system using non-RJ45 connectors but backwards compatible with hybrid cords. Until February 2008, the only standard (published in 2002) to support 10GBASE-T for a full 100m.

IEEE Ethernet standards

IEEE Ethernet standards

Ethernet is defined in a number of IEEE (Institute of Electrical and Electronics Engineers) 802.3 standards. These standards define the physical and data-link layer specifications for Ethernet. The most important 802.3 standards are:

·         10Base-T (IEEE 802.3) – 10 Mbps with category 3 unshielded twisted pair (UTP) wiring, up to 100 meters long.

·         100Base-TX (IEEE 802.3u) – known as Fast Ethernet, uses category 5, 5E, or 6 UTP wiring, up to 100 meters long.

·         100Base-FX (IEEE 802.3u) – a version of Fast Ethernet that uses multi-mode optical fiber. Up to 412 meters long.

·         1000Base-CX (IEEE 802.3z) – uses copper twisted-pair cabling. Up to 25 meters long.

·         1000Base-T (IEEE 802.3ab) – Gigabit Ethernet that uses Category 5 UTP wiring. Up to 100 meters long.

·         1000Base-SX (IEEE 802.3z) – 1 Gigabit Ethernet running over multimode fiber-optic cable.

·         1000Base-LX (IEEE 802.3z) – 1 Gigabit Ethernet running over single-mode fiber.

·         10GBase-T (802.3.an) – 10 Gbps connections over category 5e, 6, and 7 UTP cables.

Notice how the first number in the name of the standard represents the speed of the network in megabits per second. The word base refers to baseband, meaning that the signals are transmitted without modulation. The last part of the standard name refers to the cabling used to carry signals. For example, 1000Base-T means that the speed of the network is up to 1000 Mbps, baseband signaling is used, and the twisted-pair cabling will be used (T stands for twisted-pair).