My understanding is that they are making several calls at once electronically and that the sound and delay are showing them that someone has answered.

But why do I hear it? And why that particular sound?

That’s beyond my technical expertise. Perhaps it’s to tell you that it’s pootentially a spammer.

Is this on your cell phone or land line? If we’re talkin land line, lately mine is deluged with robo calls, and I thought I was signed up on the “do not call” list.

I don’t know for certain, but the sound channel going to you (whether it was a recorded message or a blank line) is being switched to a connection to a different audio feed that lets you hear them and the background noise (or the filtered background noise) where the representative is. Your ears hear the difference in the background noise between the channels as their system switches over.

Did you do that accidentally, @janbb; pootentially?
Would that be a(n) (accidental) portmanteau?

@rebbel You should know by now I never do anything accidentally!

I like it :-)

Gas?

pootiful