Once connected to the network, the switches are true plug-and-play devices which start operating at power up. They automatically determine and remember devices connected to each port and only route messages through the appropriate ports, increasing speed and bandwidth. Even under heavy I/O and data exchange, the switches and the ethernet control network maintain consistent cycle times. The switches support 10BaseT (10 Mbps) and 100BaseT (100 Mbps) on RJ45 ports. Each port independently auto-senses speed and duplex, interfacing with legacy (10 Mbps) or fast (100 Mbps) Ethernet devices. The two-port Media Converter converts 10/100BaseTX Ethernet through an RJ45 connection to 100BaseFX Ethernet over an ST multimode fiber connection for links up to 4km. Fiber optic cabling increases network distance and enhances reliability.