A subscription television system and method in which billing information regarding programs actually viewed by a subscriber of the system is accumulated over non-dedicated telephone lines. A scrambled television program signal containing a block of television program material, a program identification...http://www.google.es/patents/US4528589?utm_source=gb-gplus-sharePatente US4528589 - Method and system for subscription television billing and access
Method and system for subscription television billing and access
