Sleep mode and serial line

if I enter a sleep mode (SM=1 or SM=2), will the TX pin of the serial line be still driven by the XBEE module? I dont want to get spurious reading in my microcontroller - Shall I add an external pull-up on the XBEE TX pin?

Thanks in advance,

As long as the internal pull up is enabled (enabled by default), an external pull up is not required.

thanks for the reply. However, according to the data sheet, there is no internal pull-up on DOUT pin.
EDIT: nobody knows whether the DOUT line is driven during sleep mode?

Message was edited by: meereck