International Radiotelegraph Convention (1912)

The International Radiotelegraph Convention (1912) established international callsigns, replacing the three letter callsigns prevalent then. Major world powers were given single prefixes such as N/K/W (United States), A (Germany), F (France), B (Great Britain). British colonies were given the call signs starting with V. The convention was signed at the International Radiotelegraph Conference in London on July 5, 1912.