Nick_Pyner:
It doesn't seem to need to sniff very deeply. You have the signals on the serial port ,i.e. hardware serial, which is shared with the serial monitor on the USB port. I assume you uploaded the programme with the XBee disconnected, and therefore did not have a problem.
Yes when i uploaded the code to UNO i disconnected the XBee. So no issues.
The point i am not clear about it is this : When two objects ( Uno and Xbee ) are in communication with each other using Serial protocol, how is a third object - namely by laptop - able to access the same data ?
Serial is supposed to be a Point-to-Point protocol ...right ??