[pulseaudio-discuss] Listening to in-band audio from an output?

[Craig Matsuura]

Still being a newbie but starting to get the idea how this all comes 
together.  I reviewed the FAQ and did not find anything I thought would 
help me with the following issue.

I have two cards connected (Card A mic/spkr to Card B spkr/mic). I want 
to monitor one of the output channels (from A or B) so I can decode DTMF 
in-band, my current setup is as follows based on the FAQ for connecting 
sink and source.

pactl load-module module-loopback 
source="alsa_input.pci-0000_00_1b.0.analog-stereo" 
sink="alsa_output.usb-0d8c_C-Media_USB_Headphone_Set-00-Set.iec958-stereo"
pactl load-module module-loopback 
source="alsa_input.usb-0d8c_C-Media_USB_Headphone_Set-00-Set.analog-mono" sink="alsa_output.pci-0000_00_1b.0.analog-stereo"

The above two commands allow me to connect the sink/source from one card 
to another.  I now want to listen in-band and detect DTMF tones or 
possibly other audio capture.  How can I do this keeping my two cards 
connected as above?

Thanks,
Craig