Call Sign - International Series

International Series

International call signs are formal, semi-permanent, and issued by a nation's telecommunications agency. They are used for amateur, broadcast, commercial, maritime and sometimes military radio use (including television in some countries).

Each country has a set of alphabetic or numeric International Telecommunication Union-designated prefixes with which their call signs must begin. For example:

• Australia uses AX, VH–VN, and VZ.
• Canada uses CF–CK, CY–CZ, VA–VG, VO (Newfoundland and Labrador), VX–VY, and XJ–XO.
• China uses B, XS, 3H–3U.
• Indonesia uses JZ, PK-PO, YB-YH, 7A-7I, and 8A-8I
• Japan uses JA–JS, 7J–7N, and 8J–8N.
• Mexico uses XA–XI, 4A–4C, and 6D–6J.
• Russia uses R and UA–UI.
• Sweden uses SA–SM, 7S, and 8S
• The United Kingdom uses G, M, VS, ZB–ZJ, ZN–ZO, ZQ, and 2.
• The United States uses K, W, N, and AA–AL.

The earliest allotment of call letters was made at the 1912 London International Radiotelegraphic Convention, which provided that the call letters of stations in the international system must each be formed of a group of three letters, which shall be distinguishable from one another. The Convention made a partial allotment of call letters among nations that signed the Convention, and the International Bureau at Berne, with the consent of such nations, modified and added to this assignment of call letters by circular of 23 April 1913.

Because these assignments were originally made in the second decade of the 20th century, they often reflect a former political structure that has long since ceased to exist. For example, the V series (as in Queen Victoria) originally was reserved for the British Empire, though Great Britain itself was assigned all of B, G, and M; individual subseries of V were carved out and assigned to individual dominions and territories.

The modern successor nations often (but not always) retain these series, in some cases supplemented by additional assignments. This is why prefixes beginning with V (although with different second letter blocks) are used by Canada, India, and Australia, as well as the remaining British Caribbean colonies. In 1927, the Soviet Union was assigned the entire U series; when the USSR broke up, several former Soviet republics received blocks of U call signs. (However, Russia was not a signatory to the 1912 convention, so, in 1912, UAA–UMZ were assigned to France and its colonies, and UNA–UZZ were assigned to Austria-Hungary.) The VR codes for Hong Kong and the VO ones for the Dominion of Newfoundland, are now respectively controlled by the People's Republic of China and Canada.

The United States was represented by the military at the 1927 conference, which is why it received (or, in some cases, retained) A (for Army) and N (for Navy). The W and K for civilian stations followed as the simple addition of a dash to the Morse code letters A and N. (However, in 1912, KDA–KZZ, all of N, and all of W were assigned to the United States, but all of A was assigned to Germany and its protectorates.) International call signs for stations aboard US ships were initially assigned with W prefixes on the west coast and K prefixes in the Atlantic; land-based stations followed the opposite pattern. The distinction between Atlantic and Pacific ships was to become less meaningful after the Panama Canal reduced the distance required to cross from one ocean to another.