cannot communicate between two XBP2.4-b Znet2.5

Dear sir/madam
i bought 2 XBP2.4-B units and would like to communicate between each other.
i used X-CTU to program one of them as a Z-NET 2.5 co-ordinator AT while the other is configured as ZNET 2.5 router/end device AT.

i am using matlab to communicate with my PIC18F4455. when i use the hard wire i.e. using the USB to serial to MAX232 to PIC’s UART, the data is transferred in both ways.

then i remove the wire and connect the XBEE coordinator to my sparkfun XBEE explorer card (regulated with serial connector) while the end device, i connect it in a breadboard with the Din connected to TX of micro while Dout connected to RX of micro.

i power up the everything and tried to do the same matlab transfer with the micro. but the transfer of data with the twp Znet modules did not work.
is there anyone who can help me with this?

thanks very much