Cisco Systems offers a family of Fast Ethernet (FE) port adapters optimized for the specific requirements of campus and enterprise backbones, data centers, and Token Ring Inter-Switch Link (ISL) network topologies. The Cisco FE port-adapter options provide either one or two ports of 100BaseTX (copper) or 100BaseFX (fiber) Fast Ethernet ports per adapter. Each port can be configured for half- and full-duplex operation. Cisco Fast Ethernet port adapters may be used in an open port-adapter slot on Cisco 7200 Series Routers or in an open bay within Cisco second- and fourth-generation Versatile Interface Processors (VIP2 and VIP4) on Cisco 7500 Routers. Portability between these systems simplifies ordering and minimizes overall support and sparing costs. The PA-2FE-FX port adapter support either 10- or 100-Mbps configurations with auto-negotiation. This enables auto-selection of the appropriate network speed and duplex mode.