In order to call any land line or mobile phone in a different country, you must first enter a unique set of codes that allow you to exit the country you are calling from and then identify the country you are calling to. There are nine zones that separate the different countries in the world-numbering plan and each country has a unique country code. Mexico is in Zone 5 of the country code listings and is identified by the country code of +52.
History
The unique history behind the world-numbering plan is complicated at best, with codes being added and deleted as new nations are formed and others are dissolved. Country codes and zones have changed a number of times and as the number of people who own land and cell phone lines increase, so too must the systems for dialing. In 1960, the first book to identify country codes was created by International Telegraph and Telephone Consultative Committee (CCITT). This book, called the CCITT Red Book, was intended for international operator dialing assistance. In 1964, the first international zoning system was named, which did include South America in Zone 5, but did not yet issue Mexico a separate country code. +52 was unassigned at this time and Mexico was under the North American country code of +1. In 1968, under Recommendation E.161, Mexico was given +52 as its own separate country code.
Identification
There are nine zones in the world-numbering plan. All of the countries in North America are in Zone 1 and are assigned the country code +1 with a following three-set number denoting a specific area. Zone 1 is the only zone that has this unique coding system. Africa and some of the most of the islands in the Indian and Atlantic oceans make up Zone 2. Zone 3 consists of Southern Europe, while Northern Europe is in Zone 4. Mexico, South and Central America, as well as the American dependencies, make up Zone 5. Southeast Asia is in Zone 6, Russia is in Zone 7, East Asia in in Zone 8 and West Asia and the Middle East is in Zone 9. Due to limited access to local switches, Antarctica, Kerguelen Archipelago and Pitcairn Island have no permanent country codes. Instead, they must use satellite phones to access parent country switches to make calls.
Geography
The country code for Mexico covers a large area and population. Over 21 million people inhabit Mexico and 69 percent of these people own telephones in the form of a land line or mobile phone. There are 52 separate area codes within the +52 country code for Mexico and three of these area codes, which represent Mexico City, Guadalajara and Monterrey, are represented by a two-digit number. The rest of Mexico is represented by three-digit area codes.
Features
A Mexico phone number is made up of ten digits. The area code is either a two- or three-digit number and the phone number is seven or eight digits. If you are calling a number in Mexico City, Monterrey or Guadalajara and their subsequent metro areas, you will have a two-digit area code and an eight-digit phone number. If you are calling to any other city in Mexico, you will have a three-digit area code, followed by a seven-digit number. For example, if you are calling Mexico City from the United States, you will enter the code 011 +52 55 followed by an eight-digit telephone number. If you are calling Tecate, however, you will enter the code 011 +52 665 followed by a seven-digit number.
Considerations
If you are dialing a phone number in Mexico direct from an international country, you first must dial the exit code for the country you are in. For example, if you're calling from the United States or Canada, you'll need to dial 011 and then the country code, +52, followed by the phone number. If you are dialing a cell phone direct from an international country, you must dial the exit code, country code and then 1 before entering the phone number.
