HP JetDirect EX Plus J2591A. Ethernet print server for parallel port printer.
I used this for many years with an old HP laserjet printer. It always worked well.
Includes Jetdirect box, printer cable (DB25 to Centronics), and original HP power supply.
I don't have a printer to test it with now, but it turns on and the lights blink. I was working well when I put it away a few years ago.