How are telephone country codes assigned?

Answer 1

The International Telecommunications Union, an international standards body, assigns telephone country codes.

Broadly speaking, country codes are divided into 8 geographic zones, although there are several exceptions where a code is assigned outside its zone.

Zone 1 consists of country code +1, which is the North American Numbering Plan, including the USA, Canada, and a variety of Caribbean and nearby islands.

Zone 5 consists of the rest of the Western Hemisphere, including Latin America, and the remaining Caribbean islands. The country codes in Zone 5 are +51 through +58 (two-digit codes), plus +500 to +509 and +590 to +599.

Zone 2 consists of Africa. Country codes +20, +27, and +211 to +291 are in Africa. Additionally, country codes +297, +298, and +299 are assigned outside Africa to places whose zones had run out of spare codes.

Zone 3/4 consists of Europe. Country codes +30 through +49, +35X, +37X, +38X, and +42X are in Europe.

Zone 6 consists of the Australia/Pacific region, including Thailand, the Philippines, and all the island nations of the Pacific. Country codes +60 through +66 and +670 through +692 are in this region.

Zone 7, which is country code +7, originally was the USSR, but is now only Russia and Kazakhstan.

Zone 8 is eastern and southeast Asia, plus a variety of international services. +81, +82, +84, +86, +85X, +880, and +886 are geographic codes in this zone. Country codes +800, +808, +87X, +881, +882, +883, and +888 are for international services.

Zone 9 is central, western, and southern Asia, including most of the Middle East, plus a couple of international service codes. +90 to +95, +98, +96X, +97X, and +99X are in this zone, except for +979, +991, and +999, which are in use for or reserved for international services.

There are no country codes beginning with zero. If you see something like "country code 0044," that is really country code +44, but quoted with the location-dependent international access prefix. 00 is the most commonly used prefix, but North America uses 011, and many other countries use other prefixes. For that reason, it is least confusing to write the country code with the plus sign and without the international access prefix.

When a country breaks up or merges with Another Country, its telephone country code is returned to the ITU for future reassignment. However, the ITU has a policy that all future country codes will be 3-digit numbers. Thus, if a two-digit country code is returned to the ITU, it will be reassigned as ten different three-digit codes. That's what happened to East Germany (+37), Yugoslavia (+38), and Czechoslovakia (+42).

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)

Answer 2

The International Telecommunications Union (ITU), a quasi-governmental organization based in Geneva, Switzerland, assigns telephone country codes.

There are certain guidelines for the assignment of country codes. The code can be one, two, or three digits, but the ITU announced in the 1990's that all new codes will be three digits. The first digit of the code generally identifies a world zone, although a few codes have been assigned in different zones when there were no vacant codes in the more appropriate zone. Thus, although zone +2 is Africa, country codes +297, +298, and +299 are assigned to Aruba (in the Caribbean), the Faroe Islands (Europe), and Greenland.

Zone +1 is North America, specifically the USA, U.S. territories, Canada, and certain islands in or near the Caribbean. The only country code in this zone is +1, with the location narrowed by the following three-digit area code.

Zone +2 is Africa, with the exceptions noted above.

Zone +3/+4 is Europe.

Zone +5 is the remainder of the western hemisphere, excluding zone +1. It includes Mexico, Central America, South America, and the islands not part of zone +1.

Zone +6 is Australia and the Pacific.

Zone +7 was the USSR, but is now only Russia and Kazakhstan. The only code in this zone is +7, but Kazakhstan numbers begin with +7 7 and all other numbers are in Russia.

Zone +8 is east Asia.

Zone +9 is central and western Asia, including the Middle East.

When a country code is retired, it is returned to the ITU. After allowing a reasonable time for people to update contact phone numbers, the new code may be reassigned, or, in the case of a retired two-digit code, divided into 10 new codes to be assigned. For example, +670 was the country code for the Northern Mariana Islands, which are now in country code +1. The +670 code was subsequently reassigned to Timor-Leste (East Timor). When country code +37 (East Germany) was retired with the reunification of Germany, codes +370 through +379 were available for assignment in Europe.

Answer 3

In North America (USA, Canada, etc.), area codes are assigned by the North American Numbering Plan Administrator (NANPA), a quasi-governmental body. In the UK, area codes are assigned by OFCOM. In Mexico, area codes are assigned by COFETEL. Other countries have their own regulatory agencies that assign area codes.

In North America, area codes were assigned with the specific intent of avoiding having similar numbers near one another. Thus, 804 is in Virginia, but 805 is in California.

In the UK, more than half of the telephone area codes were assigned based on alphabetic mnemonics. For example, Chester is 01244 because 24 = CH on the telephone dial. (Many newer codes have been assigned that do not follow this rule.)

In many countries, area codes are assigned in geographic blocks. For example, in Germany, all area codes beginning with 08 (+49 8 in international format) are in southern Bavaria.

Some countries have area codes of uniform length, but other countries use variable-length codes, or have no area codes at all.