@kavala this thread in the Tutorials forum discusses two way comms using Python on the PC.
Two ways communication between Python3 and Arduino.._gaMTI4Mjk0NzQ2Mi4xNzQyNTA1NjUx*_ga_NEXN8H46L5*MTc0MjUwNTY1MC4xLjAuMTc0MjUwNTY1MC4wLjAuOTU5NTY1OTY5
A good start would be to try a Python script on the PC and 'echo' a few bytes back from your Arduino Mega board. After that try and redirect the stream to an external hardware device. Your required baud rate should not be a problem.