in a fast ethernet network, it is important that all 100base-t certified category 5 cabling use rj-45 plugs.the rj-45 plug accepts 4-pair utp or shielded twisted-pair (stp) 100 ohm cable and connects into the rj-45 connector.the rj-45 connector is used to connect stations, hubs, and switches through utp cable; it supports 10 mbps, 100 mbps, or 1000 mbps data transmission.

    figure b-1 shows the rj-45 plug and rj-45 connector.

   

    figure b-1. rj-45 plug and rj-45 connector with built-in leds

    table b-1 lists the pin assignments for the 10/100 mbps rj-45 plug and the rj-45 connector.

    table b-1. 10/100 mbps rj-45 plug and rj-45 connector pin assignments

   

    table b-2 lists the pin assignments for the 10/100/1000 mbps rj-45 plug and the rj-45 connector.

    b-2. 10/100/1000 mbps rj-45 plug and rj-45 connector pin assignments