As I explained to a friend:
By the way, may I offer a small foible correction? In Europe and Asia, people add "+" before their phone numbers as you have below. However, what should come after the + is first the country code. So, below, you should have +1 615 ... rather than +615.
For example, someone from the UK would list their numbers as +44 .... Chinese as +86.
What makes this doubly confusing for us North Americans is that the country code of the US (and Canada) is "1" which is the same as the long-distance dialing input. And, still being the world's largest market, we can spend our lives only dialing area codes and never dealing with country codes.
So, in conclusion, I suggest you change your signature and cards to read +1 615 ... for international business affairs.