For long transmission lines, you should use a slower baud-rate to decrease the transmission-error probability. Or you can get a MAX232 chip for each arduino, and transmit at the at RS-232 voltage levels, to increase signal integrity.
For long transmission lines, you should use a slower baud-rate to decrease the transmission-error probability. Or you can get a MAX232 chip for each arduino, and transmit at the at RS-232 voltage levels, to increase signal integrity.