Exiled-
I know there is a serial to ethernet converter that allen bradley makes- unfortunately it costs almost as much as an SLC-505 controller, so I took it back and just got a 505 processor. If you are just talking about downloading programs from PC to PLC, you can use a USB to serial converter. I have one and I liked it much better than trying to use the serial connections. AB Part # is 1747-UIC. Hope this helps ...