...
Example: 8137599311 would be entered in the “International Access” field for a telephone number in Japan consisting of 81 for the country code, 03 for the city code and 7599311 for the phone number.
(Note: The web site http://www.1areacodescountrycodes.com shows the country access codes and may be helpful in understanding and formatting international phone numbers.)
North American Numbering Plan (NANP)
...