On Industrial level there are typically two types of RS485 protocol. "Profibus" and "Modbus". Siemens, Rocwell, ABB, and many other PLC/DCS related companies use these as their network communication between CPU(s) and I/O(s). These protocols can be over medium such as 2-wire copper, fibre optic or CAT5 or CAT6 for Ethernet.
If you want to learn RS485 (with Modbus) itself bare bones format, I would suggest using Arduino and MAX485 chips. There are many Libraries available. Search for SimpleModbusSlave and SimpleModbusMaster.