When I physically connect (1), (2) and the computer USB, I can receive on my computer data sent by (1) at 115200 Kbps. But when I physically disconnect (1) and to (2), and link them again using the XBees the computer receives no data.
I noticed that in (1) the UART Tx and Rx are directly connected to XBee's Dout and Dint. But in (2) there are 1k resistors in each of those connections. Can such resistance be the cause of the problem?
The UartsBee is configured to use 3V, and I tested both connecting and disconnecting the DTR interrupt from the XBee to the ATMega328 (there is a jumper slot for it on (1)). The board is supplied with a 9V 200mA wall adapter. Both XBees were installed pointing the closest edges of the respective boards.