The international access code (IAC), together with the country code, the area code and the subscriber number, forms the complete international telephone number
.International Telecommunication Union
has recommended the number 00 as the international dialling code. The international access code is entered before the country code.
If a German telephone number is dialed from the USA, the international prefix 00 is dialed first, followed by the country code 49 for Germany, the area code 221 for Cologne and the subscriber number 123456, so that the complete telephone number looks like this: 00 49 221 123456.