ITU prefix - Definition and Overview

The ITU allocates callsign prefixes for radio and television stations. These prefixes are agreed upon internationally. A callsign can be any number of letters and digits but each country must only use callsigns that begin with the characters allocated for use in that country.

With regard to the second and/or third letters in the prefixes in the list below, if the country in question is allocated all callsigns with A to Z in that position, then that country can also use callsigns with the digits 0 to 9 in that position. For example, the United States own KAA - KZZ, and therefore can also use prefixes like KA1, KP4, K5, K9 and so on. The USA also owns AAA - ALZ and can therefore use AL4, AL8 etc., but can NOT use A4 or A9 as they do not own the whole of AA to AZ — they only have AA to AL.

See also: Country codes

Table of Allocation of International Call Sign Series

View as grid chart

~Note 1: Series allocated to an international organization.

~Note 2: Provisional allocation in accordance with No. S19.33:

(S19.33 Between radiocommunication conferences, the Secretary-General is authorized to deal with questions relating to changes in the allocation of series of call signs, on a provisional basis, and subject to confirmation by the following conference). ~Note 3: Three letter codes beginning with Q are for communication abbreviations, the Q Codes and not used as callsign prefixes.

~Note 4: Half series allocation.