PaulS:
No. Use Serial1, Serial2, and Serial3.[...]
You definitely need ground and power connected, too.
I wrote that other pins were not changed.
OK, thank you very much, I will try it later!
I didn't know that it need only four pins (vcc, gnd, Rx and TX!)
Edit:
I can't found good library which I can use to communicate the uart.
Do you have any?