Subsidiary communications authority

Subsidiary Communications Authorization (SCA) in the United States, and Subsidiary Communications Multiplex Operation (SCMO) in Canada, is a subcarrier on a radio station, allowing the station to broadcast additional services as part of its signal. == Background == Subsidiary Communications Authorization is the United States Federal Communications Commission's official designation for this type of service.

Source: Wikipedia — Subsidiary communications authority (CC BY-SA 4.0)