What happens when you try to call someone who has blocked my number?

I want to know if my friend has blocked my number. What would happen if they had blocked my number, and I tried to call them? Using an iPhone 5s, with the latest iOS update.

Nothing, it will just ring but they don't actually hear the call, it will go to voice mail then unless they have voice mail off. Same with msgs if they block that, your msg looks like its sent but they never actually receive it.