Eli5: Why does the coin drop after hanging up the pay phone

Question

I always see in the movies that when they hang up a pay phone, you hear a coin drop. What’s the reason for this?

In: 244

Answer 1

In high school we used this feature to save a dime and later a quarter. When I was ready to be picked up from school after an event, I would call home, let it ring two times, hangup and get my coin back. Do this again and parents would know I was ready to be picked up.