[asterisk-users] Identify remote prompts: Partial audio matching?

[Philipp von Klitzing]

Ok, here's the challenge:

I would like to be able to find, match - and then react - upon prompts 
that are presented by the outbound/remote side of a call. Think mobile 
phone and "This user is temporarily unavailable".

Collecting a limited number of known prompt snippets should not be a 
problem, but how would you then detect their presence in a longer 
recording (or live audio stream)?

Recently there was an at least slightly related posting on this list, if 
I recall that correctly, but I have simply not been able to turn this up.

Philipp

P.S.: This is all about audio analysis, not about cause codes.