/dev/dsp relation to mic/line-in
 

I am planning to use parrot.c as a base for doing some
data capture off of line-in. I find that parrot.c
(from:http://www.oreilly.de/catalog/multil...pt/ch14-05.htm)
will work only with mic. I tried setting capture to line-in with alsamixer but this did not work.
Is there something endemic about dsp (that I am mentally ignoring} that prohibits use of line-in with that program code? Seems to me that I tried programming the sound card once before and used line-in without a problem.