Target Store "Bings"

Can any current/former Target employees explain the insanely loud “bings” that play over the in-store PA at seemingly random times? I was nearly deafened this evening by an incessant series of “bings” while standing near a speaker.

I worked at target while in highschool. I’m not sure if this is what you heard…but if the operator doesn’t press the button to turn off the intercom before hanging up the hand set, a loud bang will be heard throughout the store.