The MGX-RPM-1FE-CP (one-port, Fast Ethernet-Co-processor) back card is an MGX8850/RPM-PR back card that off-loads some processes from the Route Processor Module (RPM-PR). This back card is designed to be used with an MGX8850 that is equipped with one or more RPM-PRs and that terminates some number of T1 lines. The MGX-RPM-1FE-CP is only supported with the MLP encapsulation. The MGX-RPM-1FE-CP back card contains one Fast Ethernet (100Base-Tx) interface. The interface has an RJ45 connector that is used to connect the card to a Category 5 un-shielded twisted pair (UTP) cable. Both half- and full-duplex operation are supported.