A callbook is a directory of radio station

Radio station

Radio broadcasting is a one-way wireless transmission over radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both...

 call signs

Call Signs

Call Signs is the third studio album by Melbourne electronica band Black Cab, released in 2009.The album evokes the atmosphere of the former totalitarian state of East Germany, set to a soundtrack of post-punk and atmospheric electronics. In an interview, the band explained the album's sound was...

. Originally a bound book that resembled a telephone directory

Telephone directory

A telephone directory is a listing of telephone subscribers in a geographical area or subscribers to services provided by the organization that publishes the directory...

, it contains the name and addressees of licensed radio stations in a given jurisdiction (country). Modern Electrics published the first callbook in the United States in 1909. Today, the primary purpose of a callbook is to allow amateur radio operators to send a confirmation post card, called a QSL

QSL

QSL is one of the Q codes used in radiocommunication and radio broadcasting. A Q code message can stand for a statement or a question . In this case, QSL? means "do you confirm receipt of my transmission?" while QSL means "I confirm receipt of your transmission". Some also take it to mean "Query...

card to an operator with whom they the have communicated via radio. Callbooks have evolved to include on-line databases that are accessible via the Internet to instantly obtain the address of another amateur radio operator and their QSL Managers. The most well known and used on-line QSL databases include QRZ.COM, IK3QAR , HamCall, F6CYV, DXInfo, OZ7C and QSLInfo.