Telephone area codes are unique numbers assigned to different countries and different regions within a country for convenience. The land line telephone systems are entirely dependent on these telephone area codes to successfully complete your call. Area codes were introduced in the United States by the Bell System in 1947. The first direct dial long distance call occurred in 1951.
There was no specific criterion for assigning codes to countries. They were simply dished out to countries making sure no two countries had the same telephone area code. You will notice that a majority of countries have two digit area codes while others have 3 and the United States of America, as an exception, has only one, the number 1. Each country is assigned an area code that can easily be found on the internet.
While using the telephone area code it is highly advisable to start with a + sign before the area code for that country. For example, while placing calls to the United States you will key in the number as follows, +1 followed by the number of the person you intend on calling. Within a country area codes go further to differentiate different. These codes are however used for land lines.
Mobile phones have their own criterion for identifying users, which is the unique telephone number. This number can be easily located by the system. The area code is not required while calling a mobile phone within the same country. However, when making a call an international call, the telephone area codes are required.
Telephone area codes are a crafty piece of ingenuity. They have helped connect people from the time telephone cost were over $10 per three minutes up to now.