An interactive television system includes "connected" receiver units capable of establishing bi-directional connections to remote information stores, such as Web servers, and "disconnected" receiver units unequipped to make such connections. The system supports the use of broadcast triggers that include...http://www.google.de/patents/US20040261130?utm_source=gb-gplus-sharePatent US20040261130 - Providing multiple levels of interactive television service using triggers and trigger filters
