Well - Will not suggest doing it here. But, once we were getting blank calls - with someone just laughing coarsely occasionally. I closed up all windows/doors.. setup my tape recorder in full volume for a second... and then pressed pause.. Next time the call came, I picked and made sure it was the same person.. then took the phone next to the speaker and released the pause... for five seconds... Never received a call again... P.S. I was a teenage kid. Would not do it now... Who knows what can happen to the guy at the other end.