I did this with a https://en.wikipedia.org/wiki/Breakout_box#/media/File:KL_Br... in between. With ECP-DMA, or some such. Red-green blinking lightshow at about 4Mb/s! :-)

Edit: Yes, I'm aware that box says RS-232, but with gender-changers, the dip-switches and some cable-bridges, you could abuse it for 'parallel'.