Some countries may require that any carrier selection codes precede the international call prefix.
[3] Additionally, the GSM mobile telephony standard allows the use of the plus sign as the international call prefix, which makes it easier to store telephone numbers in a uniform format that works from anywhere in the world.
[citation needed] The fictitious number (02) 3456 7890 in Sydney, Australia, is published in the form +61 2 3456 7890 for international use.
In countries participating in the North American Numbering Plan, such as the United States, Canada, and some Caribbean nations, this number is dialed as 011 61 2 3456 7890, with 011 being the international call prefix for the NANP and 61 being the country calling code of Australia.
From most of the rest of the world, the international access code is 00, so that the call is dialed as 00 61 2 3456 7890, as recommended by the regulations of the ITU.