A method and apparatus to enable billing of subscribers of pay-per-view television systems or the like on a non-real-time basis. A scrambled television signal is received at a subscriber terminal from a headend. The received signal is selectively descrambled in response to subscriber action indicating...http://www.google.co.uk/patents/US4710955?utm_source=gb-gplus-sharePatent US4710955 - Cable television system with two-way telephone communication path
