How Telephone Country Codes Work

By: Dave Roos
A woman on office talking through a landline telephone.
In the early days, phone calls traveled as analog signals across copper wire. Compassionate Eye Foundation/Her / Getty Images

In 1980, Americans spent 2 billion minutes making international phone calls. By 2004, that figure jumped to 64 billion minutes [source: Federal Communications Commission]. Why the huge increase?

International calls are cheaper than they were in 1980. That makes it easier for foreign-born citizens to call the family back home. An increase in international business and travel is also responsible. The most popular international call markets from the United States are Canada, Mexico, the United Kingdom, Germany and India. These countries account for 38 percent of all international calls [source: Federal Communications Commission].


The very first transatlantic telephone cable went operational in 1956. It could only handle 36 calls at a time and cost $12 for the first three minutes (the equivalent of $92 in 2007). That's better than the very first transatlantic calls made via radio signals in 1927. Those cost $75 for the first three minutes ($872 in today's money!) [source: AT&T and The Inflation Calculator].

It's not easy to construct and maintain a worldwide telephone network. Keeping up with the increasing demand for international phone calls has required the cooperation and collaborative efforts of governments and private telecommunications companies around the globe. Organizations like the International Telecommunication Union (a United Nations agency) help set the international numbering standards and technology protocols that safely route calls across oceans and continents.

How does the international numbering systems work? How was it established? And, why is it important? Go to the next page to find out.