I remember an episode of the Simpsons. In this one scene Snake is robbing the Kwik-E-Mart... and he asks Apu for the money, then Apu says ok. Apu then presses a button, and you hear "SILENT ALARM ACTIVATED" over a loud speaker.
Sound file: http://download.lardlad.com/sounds/season13/poppa16.mp3
Does anyone know which episode this is from? I can't remember.