-redundant as I stepped away and found Amigaski and Red beat me to it- lol
Hmm.... yeah - I'd normally be hesitant hooking that IBM looking thing to an Amiga. You'd think you'd want a diode on one of those +5v lines at least, but I bet you'd be okay with a Joystick/Mouse combo hooked to it. A passive joystick w/ no circuitry in it that wouldn't use the voltage and a mouse which does... yeah - I'd say it's worth a try. Try it on a machine though where the CIA's are easily replaceable
Reminds me of this 4 way splitter for some 4-player games back in the day... anyone remember those and the games that took advantage of 'em? Micromachines or a similar game and at least one Tennis game IIRC.