Okay, so the insane code may look like this:
void setup() {
// initialize serial:
Serial.begin(9600); // For monitoring on PC
Serial1.begin(9600); // Sender
Serial3.begin(9600); // Receiver
}
void loop() {
Serial1.println("Doesn't matter what you say here."); // Send from Serial1 to Serial3, so wire them up accordingly, directly, without anything like a MAX232
delay(2000);
if (Serial3.available()) {
// get the new byte:
char inChar = (char)Serial1.read();
Serial.println(inChar); // Send to PC what Serial3 received
}
}
To simplify the situation, I just sent Serial1.println('A'); during testing