The DP83840A is a Physical Layer device for Ethernet 10BASE-T and 100BASE-X using category 5 Unshielded, Type 1 Shielded and Fiber Optic cables. This VLSI device is designed for easy implementation of 10/100 Mb/s Ethernet LANs. It interfaces to the PMD sublayer through National Semiconductor's DP83223 Twisted Pair Transceiver, and to the MAC layer through a Media Independent Interface (MII), ensuring interoperability between products from different vendors. The DP83840A is designed with National Semiconductor's BiCMOS process. Its system architecture is based on the integration of several of National Semiconductor's industry proven core technologies: