Hello everyone.
I am trying to make the 2 XBee modules communicate themselves, but I have no success.
Is there any secret to do that? Changed network ID, channel, nothing.
Any help would be appreciated. 
What is the full part number(s) and firmware versions used on the radios in question?
Reply below,sorry.
Hello dear mvut. I am using XBP09-DMWIT, firmware v. 8062.
The radios can communicate between themselves, the problem occurs only with Arduino Mega.
Thank you for your help and support.
Have you looked at what is being sent out of the UART of the Arduino to make sure that it is valid data?
How are you connecting the XBee to the Arduino? Are you connecting it direct or using an XBee shield?