This is an HP print server - takes any standard non-networked parallel printer and gives it full network connectivity. Back in the day these were everywhere - every office used them to make printing easy and convenient.
The J2591A is an early model supporting 10 BaseT networking only using the modern standard of RJ45 jacked network cable or the older BNC type connector cable. Access to settings is had through telnet connection (see photos), it does not feature a web browser based setting page.
Factory reset and tested working 100%.