I wasn't aware Mexico had intended to join NANA and use the NANP. It's a shame they didn't.

For non North Americans: the telephone networks use an international numbering plan so Canada, the US, and about 18 smaller countries use a single numbering scheme and issue area codes out of the same pool. So for me in the US dialing Canada or Bermuda is the same as dialing somewhere in the US.

It is much nicer than the international dialing system where each country has its own rules about what parts of the number are area, local exchange, etc. I wish the old ATT had designed a larger scale numbering plan that could have been worldwide and everyone could have adopted it.

(Imagine if IP addresses were different lengths and subnets were described differently based on the country of connection)