Data flow

I have build up a transmitter which transmits frequencies to radio. I
can swtich OFF and ON the transmitter. When flow graph runs the data is
transmitted in the air by usrp and RF400 daughter board. The audio is a
wav file saved on host or by direct input from mic. If i switched off
the transmitter then where does the data ends up because data is still
coming to input of UHD sink.

Best Regards,