Interface with credit card terminal?

Okay so I have ended up in the possession of a FirstData FD-100 credit card terminal, and I have been trying to figure out how one would, or if it would even be possible to, connect it to a computer or raspberry pi and print arbitrary things with its thermal printer and maybe even receive input from the keypad. I have so far turned up very little information, though my information-gathering skills are not too great.

Has anyone maybe got any ideas?