Forum: GNU Radio how to monitor the output of tx module

Hi,

My RFID communication system uses the following blocks. I can monitor 
the
signal output by rx module using self.connect(rx, rx_out). rx_out is a 
log
file generated by rx_out = gr.file_sink(gr.sizeof_gr_complex, 
"./rx.out").
How could I monitor the output of tx module? Thanks.

self.connect(rx, matched_filt)
self.connect(matched_filt, command_gate)
self.connect(command_gate, agc)
self.connect(agc, to_mag)
self.connect(to_mag, center, mm, tag_decoder)
self.connect(tag_decoder, self.reader, amp, to_complex, tx);

Pengyu