Although the International Telecommunication Union (ITU) has attempted to promote common standards among nation states, numbering plans (and international calling codes) take different formats in different parts of the world. For example, the ITU recommends that member states adopt 00 as their international access code. However, as these recommendations are not binding on member states, some have not, such as the United States, Canada, and other countries and territories participating in the North American Numbering Plan.
