Xbee Problem

Projects General Guidance
1

I have the hardware set up and communication between two Arduino UNO each with a Sparkfun Xbee Shield. All radios are XBee Series One. The radios were not reconfigured, just used right out of the box. A third radio is connected to a PC (Sparkfun XBee Explorer) running X-CTU to monitor that the Tx is really sending data (and it is).

Both Tx and Rx are using sketches and the Xbee library from GitHub - andrewrapp/xbee-arduino: Arduino library for communicating with XBee radios in API mode by Andrew Rapp.

The issue is that the Rx ignores the incoming messages. I have modified the Rx code to trap this error. I discovered that this works:

void loop() {
    
    xbee.readPacket();
    
    if (xbee.getResponse().isAvailable()) {
      // got something
      flashLed(LED_0, 1, 100);
...
      }
   }

LED_0 blinks on every Tx
But the next line of code does not make the LED blink at anytime.

void loop() {
    
    xbee.readPacket();
    
    if (xbee.getResponse().isAvailable()) {
      // got something
      //flashLed(LED_0, 1, 100);
      
      if (xbee.getResponse().getApiId() == RX_16_RESPONSE || xbee.getResponse().getApiId() == RX_64_RESPONSE) {
        // got a rx packet
       flashLed(LED_0, 1, 100); 
...
      }
   }
}

Any hints on why the Rx can't find an "rx package"?

Thanks In Advance,