Serial1 is not reading the Xbee on a Arduino Due I am trying to test simple communication between a Xbee on my Arduino Due and a Xbee linked to XTCU. I attached jumper wires from RX and TX to RX1 and TX1 (Serial 1 hardware port) but I cannot send or receive data between the Xbees. I tested the Xbees previously with an Arduino Zero talking to the XTCU and it worked flawlessly. 

Extra information: I am using a Xbee Shield on my Arduino Due (as shown in the picture)

char c,d;

void setup() 
{
// put your setup code here, to run once:
Serial.begin(9600);
Serial1.begin(9600);

}

void loop() 
{
// put your main code here, to run repeatedly:
if (Serial1.available())
{
 c = Serial1.read();
 Serial.print(c);
}
else if (Serial.available())
{
 d = Serial.read();
 Serial1.print(d);
}

}


My wiring is attached. What am I doing wrong?
I fixed my problem. I stupidly left the Xbee Shield on DLINE instead of UART. Now there is communication between the radio modules. I have another question. When I type a character into XTCU, it "receives" the exact character from the Arduino Due. I have used this basic code with other Arduinos before and this has never happened.

Extra information: The serial monitor solely prints out received data. 

I attached an example.