Pc-Arduino Mega 2560-USB host shield-Arduino mega 2560 For more information the printer has other arduino mega inside, the bridge would be: I didn't say the machine before, because it is not relevant, work with simple serial communication, I did it in other systems, but It my first time with arduino and I don't know how it work. The USB Host Shield contains all of the digital logic and analog circuitry necessary to implement a full-speed USB peripheral/host controller with your Arduino. If you don't want to answer because I think that you are lose your time with me, I understand it, but not be rude I am an engineer, I know perfectly how to do smart questions.
If you can't, or not understand, the question because I didn't explain the this in the correct way for you, you can ask and I will always answer as well as I can, first at all because I am writing in a language that is no my language, is not necessary be rude. Ok I think that you are taking this in a bad way.