Mega2560 / Prusa - via standard serial port?

Hi Folks!

I have an 'old' computer that I wanted to connect to a Reprap via a standard serial port.

I have a Prusa i3 (and an older i2) I believe running Sprinter firmware (it may be Marlin - it's been a while), RAMPS 1.3/1.4, and the Mega 2560.

Since the old computer doesn't have USB - can I just connect to the serial pins on the Mega 2560 to send commands (/ receive ACK)? or do I need to do something with the firmware or otherwise to tell it to use serial instead of USB communications.

Thanks!
John H

computer serial is -12v and +12v

arduino mega serial is 0 and +5 volts


You need a hardware converter that converts the voltages (max232 or something similar)


The converter can just be plugged into AUX-1 PIN D0 and D1 are also knows as TXD0 ad RXD0, the serial inputs to the mega.

No firmware modifications are required.