Multiple receivers may be enabled to receive satellite-based digital audio
radio (SDAR) services under a single subscription. For example, an SDAR
service provider can enable multiple vehicles, a home-based digital
radio, or a portable digital radio, singly or in any combination.
Multiple receivers transmit information to each other. One receiver is
designated as a primary receiver, and the other receivers are designated
as secondary receivers. The SDAR service provider transmits a list of
associated secondary receivers to the primary receiver. The primary
receiver enables the associated secondary receivers to receive SDAR
services by placing them in an authorized state. The secondary receivers
must periodically communicate with the primary receiver to remain
authorized. A secondary receiver that fails to communicate with the
primary receiver within a prescribed time period is switched to an
unauthorized state. In this unauthorized state, the secondary receiver no
longer performs as an authorized receiver.