Different countries apply different modes of writing their telephone numbers. What's behind of this? In most cases it is a random choice of a random man who created the notation.
USA was the first country which had to deal with a problem of... too long telephone numbers. In 1910 over 7 mln Americans had their own telephone numbers consisting of 7 digits. The man who made these numbers more legible and easy to remember was Ladislav Sutnar.
Ladislav Sutnar was the pioneer in the field of Information Design.
He was the first designer, who used brackets, icons, little pictures and lines to organize information and present it on various types of carrier. Nowadays his ideas are applied and developed by information designers and architects in new media.
Sutnar was the first who came up with the idea of separating the beginning of the number, which constitutes the local code.
There is not much information about Suntar in the Polish internet (today it's only 203 results). He was born in Czech in 1897 and died in the USA in 1976. He graduated from Prague School of Decorative Arts. He continued his education in Prague State School of Graphic Arts, where he became a professor at the age of 26. After Hitler's invasion of the Czech Republic, he immigrated to the United States. There he worked for, among others at Bell Telephone Company.
When creating different language versions for websites we should remember that The national conventions for writing telephone numbers vary by country.
For instance in Germany dots are used to separate numbers and the area code, and dash to separate the country code:
French use spaces to separate the numbers:
+33/ (0)1 44 08 79 54
In Italy phone number is separated from the area number:
In Sweden they use spaces and dash to separate the area number:
08-302 208 79