2010-10-06 PinDr0p is a system for tracing call pat ...
PinDr0p is a system for tracing call paths across multiple phone networks released by Georgia Tech. The first application they mention is detecting "vishing" (Voice phishing), the call center of your bank should not be routed via a satellite path and a voip exchange in Lagos.
My first thought was: "will it detect the clicks, clangs and noises from old electromechanical switches". That might be even easier than the modern delays, jitter and packet loss.Found via Voice-routing call fingerprint system fights 'vishing' - The Register. I love the 'Actually, I don't think my bank has a Lagos call centre' byline.
Update I asked the above question about electromechanical exchanges to the media contact for the research, who forwarded it to the researcher. The researcher found it an interesting question and thinks it is doable.