https://gitea.retro-commodore.dk/RCEU/RCEU540-Amiga-4-Player-Adapter/?display=rendered
RCEU/RCEU540-Amiga-4-Player-Adapter: An adapter that plugs into the Amiga's parallel port to grant...
RCEU540-Amiga-4-Player-Adapter - An adapter that plugs into the Amiga's parallel port to grant 3rd and 4th joystick port.