Page "Satellite radio" Paragraph 9

Each receiver has an Electronic Serial Number ( ESN ) Radio ID to identify it.

When a unit is activated with a subscription, an authorization code is sent in the digital stream telling the receiver to allow access to the blocked channels.

Most services have at least one " free to air " or " in the clear " ( ITC ) channel as a test.

For example, Sirius uses channel 184, Sirius Weather & Emergency.