Apart from the possibility to add a multiplexer I'm considering to use my Arduino Mega as a second arduino in my project. This way I'm sure I can use any Arduino compatible component, although the price is that software complexity increases from two to three components that need to communicate. I'm looking to answer the following questions: 1: I've read somewhere that the TX and RX pins output the same data as the USB on an Arduino, I guess this is the same on the UDOO Neo? So I should not connect the Arduino Mega to the TX and RX pins, but e.g. pins 16 and 17, shouldn't I? 2: The Arduino Mega has labeled pins 18 and 19 as TX1 and RX1, I guess that corresponds to using Serial1, but I can use pins 1 & 0 as well (TX0, RX0) as well can't I? 3. Making providing power to the entire setup easier I want to provide power from the Neo to the Arduino. Am I correct that I can connect Neo's 5v pin to the Mega's 5v pin and a GND to GND and all will be fine? The Neo is 3.3v, the Mega is 5v. 4. An alternative is connecting the Mega to the USB of the Neo. But, will the Neo provide enough power on the Mega? Will the Mega show up under Linux as another serial stream?