A billing system for use in a chargeable program broadcasting is capable of reliably billing a subscriber for program reception while preventing unauthorized reception thereof. A receiving terminal includes a primary terminal 100 and a secondary terminal 150. The primary terminal 100 receives a compressed...http://www.google.com/patents/US6002694?utm_source=gb-gplus-sharePatent US6002694 - Interactive chargeable communication system with billing system therefor
