hi guys, Thanks for your response 
my question is about the CTS pin in xbee 2 ZB; in my project i need to use it, but i don’t know where to connect it with pic 18f4520 (which pin), any idea ^^.
CTS is an output from the radio. It would need to be connected to an Input on the UART of the Pic.
thanks for your answer;
i have just one UART in my pic; so i will not able to use it
juste for his use we d’ont need to configure any registre or interruption ?