What is "fidelipac"

The Fidelipac, commonly known as a "NAB cartridge" or simply "cart", is a magnetic tape sound recording format, used for radio broadcasting for playback of material over the air such as radio commercials, jingles, station identifications, and music. Fidelipac is the official name of this industry standard audio tape cartridge. It was developed in 1954 by inventor George Eash (although the invention of the Fidelipac cartridge has also been credited to Vern Nolte of the Automatic Tape Company), and commercially introduced in 1959 by Collins Radio at the 1959 NAB Convention. The cartridge was widely used at radio stations until the late 1990s, when such formats as MiniDisc and computerized broadcast automation predominated.