Okay I see. Actually, in a previous project I succeeded to have the Arduino grab the data online and then print it out, without the PC doing the processing beforehand. It wasn't the smoothest program ever so there's that...
Maybe wishful thinking on my part, but I was wondering if I could just get rid of the Arduinos altogether and run everything from the PC, via multiple USB ports, and using this cable from Adafruit to connect from USB to the TTL connections of the printers. Too much?
Thanks in advance
A