Where you are talking to xbee in api mode, you need to use microcontroller to build the packet… Apart from that you can see received packet in the X-CTU – Terminal… Here click Hex, you will also see hex received data and sent data in the terminal window
I also wonder if I enable the DIO pins on an xbee, what are pin2 and pin3 - UART data in and UART data out for? What’s the difference between DIO line passing and UART?