Communication between SLC5/03 and Arduino ?

HI EVERYONE!!
I have a project and i'm stuck on smthg
I'm trying to connect an Arduino uno to Allen Bradley SLC 5/03,is there any solution via RS232 or DH ? because SLC 5/03 have only RS232 port or DH485 port
otherwise can I use an thernet port : trying to connect an SLC 5/03 from the RJ45 (DH-485) port to Ethernet. Is there some kind of module or converter available to do this? I need a solution other than replacing it with the SLC 5/05.