That's an old "fixed SLC-500" controller.
The old DOS-based "APS" and "AI-500" software packages from Allen-Bradley and ICOM software, respectively, were used to program these before Windows came around.
The modern software that can still program them is called RSLogix 500.
The jack on the front of the controller is a DH-485 network port. The best interface to that port is a 1747-UIC USB/DH485 interface.
Although that jack looks like Ethernet, DO NOT plug an Ethernet jack into it. It has 24V DC on one of the pins and will smoke an Ethernet port.