The MGX-RJ45-4E back card provides up to four IEEE 802.3 Ethernet 10BaseT interfaces.The RJ45-4E back card contains the enabled LED, standard on all back cards, and one status LED for each port, called the "link" LED. After system initialization, the enabled LED goes on to indicate that the RJ45-4E back card has been enabled for operation. When a 10BaseT port is active, its link LED is on when a port on the RJ45-4E back card is receiving a carrier signal from the network.The interface connectors on the RJ45-4E back card are four individual RJ-45 receptacles. You can use all four simultaneously. Each connection supports IEEE 802.3 and Ethernet 10BaseT interfaces compliant with appropriate standards.