Thanks for reminding me about this. I originally wanted it to implement a sort-of radio repeater. Hook up a computer - or, in this case an N900 - to a two-way radio. The radio's earphone output to the mic input and vice-versa. Imagine Anna and Elsa want to talk through two-way radios but are just out of range from each other. Put a repeater somewhere in the middle. When Anna talks, Elsa can't hear her, but the repeater can. It will record Anna's message and then play it back, so Elsa can hear (and so can Anna, which may feel a bit strange but may also be a useful feedback about the connection quality).

In fact the connection quality test was my primary reason for wanting this in the first place Unfortunately other things got in the way and I could not proceed to the implementation for a while and then I forgot about it altogether. Now you've reminded me, I pretty much have to