<?xml version="1.0" encoding="ISO-8859-1"?>

<example id="dial_tone_ex"><title>Dial Tone Output</title>

<programlisting>

#!/usr/bin/env python

from gnuradio import gr

from gnuradio import audio

def build_graph ():

    sampling_freq = 48000

    ampl = 0.1

    fg = gr.flow_graph ()

    src0 = gr.sig_source_f (sampling_freq, gr.GR_SIN_WAVE, 350, ampl)

    src1 = gr.sig_source_f (sampling_freq, gr.GR_SIN_WAVE, 440, ampl)

    dst = audio.sink (sampling_freq)

    fg.connect ((src0, 0), (dst, 0))

    fg.connect ((src1, 0), (dst, 1))

    return fg

if __name__ == '__main__':

    fg = build_graph ()

    fg.start ()

    raw_input ('Press Enter to quit: ')

    fg.stop ()

</programlisting>

</example>