Gigabit Ethernet
The fifth specification, Gigabit Ethernet, is a new addition to the IEEE 802.3 specification and will be designated 802.3z.
It supports 1 Gbps baseband transmission.
This new type of Ethernet is used primarily as a backbone to connect networks over fiber optic cable but theoretically should work with cat 5 UTP.
The standard employs the CSMA/CD access method and is backward compatible with 100BaseT and 10BaseT technologies.