Just found out that my problem was with my I/O settings!!! 
I had a digital Input pin enabled (DI00), Pull up resistor 0 and Samples Rate before TX 5.
Samples Rate before TX is sending the strange characters.
I managed to solve it by setting Samples Rate TX to 0, but now i am unable to use the I/O pins, just the serial.
What are the correct settings to use xbee I/O pins and also have godd serial communication without strange characters?