Part 10 of the Industrial Networking: Serial to Ethernet training series
RS-485 is basically only a master-slave situation unless complicated token passing scheme is used. Ethernet allows for multiple devices to initiate a message and share another device seamlessly.
Long-time automation trainer Doug Bell, Interconnecting Automation, covers the basics of Industrial Networking with AutomationDirect’s Chris Harris. This video is produced by CFE Media to be noncommercial and educational. Runtime is approximately 3 minutes.