all arduinos would be powered from the same power supply so phantom powering shouldn't happen.
can you please check my schematic.
O/P to I/P requires no resistor.You do know you will need a common ground return path between the two Arduinos?
As long you don't use mains to power it, you can just shove a wire into the earth and connect it to the arduino ground. This will cause the arduinos to have a common ground without another wire."OMG, but I live in the middle of the Sahara Desert .