3Com 3C16476BS-US User Guide - Page 59

GLOSSARY 10BASE-T The IEEE specification for 10 Mbps Ethernet over Category 3, 4 or 5 twisted pair cable. 100BASE-TX The IEEE specification for 100 Mbps Fast Ethernet over Category 5 twisted-pair cable. 1000BASE-LX IEEE 802.3z specification for Gigabit Ethernet over 9/125 micron core single-mode fiber cable. 1000BASE-SX IEEE 802.3z specification for Gigabit Ethernet over two strands of 50/125 or 62.5/125 micron core multimode fiber cable. 1000BASE-T IEEE 802.3ab specification for Gigabit Ethernet over 100-ohm Category 5, 5e or 6 twisted-pair cable (using all four wire pairs). autonegotiation Autonegotiation is where two devices sharing a link, automatically configure to use the best common speed. The order of preference (best first) is: 1000BASE-T full-duplex, 100BASE-TX full-duplex, 100BASE-TX half-duplex, 10BASE-T full-duplex, and 10BASE-T half-duplex. Autonegotiation is defined in the IEEE 802.3 standard for Ethernet and is an operation that takes place in a few milliseconds. Autonegotiation must be enabled for the 1000BASE-T ports to operate at 1000 Mbps, full-duplex. bandwidth The information capacity (measured in bits per second) that a channel can transmit. The bandwidth of Ethernet is 10 Mbps, the bandwidth of Fast Ethernet is 100 Mbps and Gigabit Ethernet is 1000 Mbps. category 3 cable One of five grades of Twisted Pair (TP) cabling defined by the EIA/TIA-568 standard. Category 3 is voice grade cable and can only be used in Ethernet networks (10BASE-T) to transmit data at speeds of up to 10 Mbps. category 5 cable One of five grades of Twisted Pair (TP) cabling defined by the EIA/TIA-568 standard. Category 5 can be used in Ethernet (10BASE-T) and Fast Ethernet networks (100BASE-TX) and can transmit data at speeds of up to 100 Mbps. Category 5 cabling is better to use for network cabling than Category 3, because it supports both Ethernet (10 Mbps) and Fast Ethernet (100 Mbps) speeds.