No, just random knowledge flying around between my ears. Also, I was making assumptions - if the SIT tone was detected in early media then I assumed it was a traditional SIT; if the SIT tone was detected after the b leg answered then I assumed it was some sort of answering machine or voicemail. It was never meant to be scientific - I was just experimenting with voice broadcasting in the very early days of FreeSWITCH and OpenZAP.

-MC