The international telephone prefix is a code that must be added before a national telephone number in order to make calls abroad: each country has one, for example Italian mobile numbers have the prefix +39 (or 0039), those of the USA (and Canada) have the prefix +1 and so on. But how was it decided which prefix each country corresponds to? The ITU regulates the assignment of prefixes in the various geographical areas of the planet (International Telecommunication Union), an international organization founded on May 17, 1865 in Paris, now part of the UN and headquartered in Geneva, Switzerland. The ITU has defined country codes through specific standards, known as E.123 (which defines the notation of numbers, i.e. how they should be written) and E.164 (which defines the current “map” of prefixes, created in 1964).
What are the international dialing codes: from Zone 1 to Zone 9
To understand how the world is divided today, we must look at the zones established in 1964, which, despite now obsolete terminology, remain the basis of the system. Zone 1 identifies the North American Numbering Plan or NANP and uses the single country code 1, followed by a three-digit prefix, to cover the United States, annexed territories, Canada, and much of the Caribbean. Moving towards Zone 2, we find the use of two-digit codes (such as 20 and 27) and several three-digit series to serve mainly the African continent, but also distant territories such as Greenland, the Faroes and the British Indian Ocean Territory. Europe, given its high density of nations and infrastructure, occupies entirely Zones 3 and 4. Here two-digit codes are used (including our 39, France’s 33, Germany’s 49 and the United Kingdom’s 44) and series of three-digit codes to cover the rest of the continent.
Continuing our “virtual journey” among the international prefixes, we reach Zone 5, dedicated to Central and South America. The area of South-East Asia and Oceania falls within Zone 6. The situation of Zone 7 is very particular, which uses the initial figure 7 to serve an immense area which today corresponds to Russia and Kazakhstan, a legacy of the Soviet bloc. East and South Asia, on the other hand, fall into Zone 8, which includes giants such as China and Japan. Finally, Zone 9 covers a large and heterogeneous area that includes the Middle East and western and central Asia.
You can find the official list of international prefixes on the International Telecommunication Union website.
The birth of international prefixes
Retracing the birth of international prefixes, we must leap back to 1960, when the CCITT (Comité Consultatif International Téléphonique et Télégraphique), predecessor of the current standardization sector of the ITU, i.e. ITU-T, introduced the first “International Codes” during its second Plenary Assembly in New Delhi. Initially designed only for Europe and the Mediterranean basin, it would have been necessary to wait until 1964 to see the adoption of a real system of world numbering zones, whose borders were roughly drawn on the basis of geographical position.
The criterion for distributing numbers followed the continental mass, but the internal division depended on the capacity of each nation’s network at that precise historical moment. It is interesting to note how the hierarchy of world powers was reflected in the telephony sector: hegemonic nations received preferential treatment, while China managed to force the official non-listing of Taiwan, which was still assigned the code 886.
