Robodialers trigger off the word "hello". When I get a call from a number not in my contacts I tersely answer "WHAT???" and if nobody talks, I hang up and block the number If it IS someone I know we have a laugh at me being a grouchy pain in the [***]. If you get a call from someone not in your contacts, answer with anything but hello and the recording will not kick in for 7-8 seconds. Maybe "Who is this?" or "Do I know you?"