Non-ITU prefix


Prefixes that are used for radio and television are usually allocated by ITU. They also form the basis for, but do not exactly match, aircraft registration identifiers. But in some cases, especially among amateur radio operators other, by ITU unallocated, callsigns are used when operating from disputed areas or countries that are internationally not recognized.
They can be:
Prefixes for those stations are either unallocated or unavailable by ITU definitions.

ITU unallocated and unavailable call sign prefixes

Unallocated: The following call sign prefixes are available for future allocation by the ITU.
Unavailable: Under present ITU guidelines the following call sign prefixes shall not be allocated.