WARNING: Technical mumbo jumbo ahead.
I have a buddy who has been working a problem for a while now where a tech has a conference bridge keeps dropping calls because we are not responding to Telco that the call is answered. We have been very confused and couldn't figure out what was wrong.
Today another guy posts and explains, it's not a conference unit issue because they are routing the call to what is called a "Dead Level Announcement." A "Dead Level Announcement" is supposed to play when you dial a number not in use. When you dial from your home it says something along the lines of "You have reached a number that is no longer in service."
The tech was trying to CHEAT his way to connect to the conference gear using the announcement path as a connection media. I would say it was a smart idea and good try, but it didn't work. Specifically because when you ring a "Dead Level Announcement" YOU ARE NOT ANSWERED BY ANYTHING as far as the PBX is concerned. So we never told Telco the call was answered, so Telco dropped the call.
If he had told us that when he was asked the question "How are you routing this call, what is different between this one and one that does work?"
Despite the tech's furious babbling, it doesn't work and AIN'T GONNA WORK.