How to know if a phone number is a domestic number or international one

Question

I am using PhonyRails (Phony) and I am trying to achieve the following:

If a domestic phone number is sent to me, I want to know whether its domestic or international. Why? Because if its domestic I want to convert it to the E164 standard.

How can I do this?

Answer 1

If you are calling from the US, if the number starts with 011, then it's an international call. Other countries might start with different codes.