Method for controlling copying of protected information transmitted over a communications link
US4890319A · kind A · utility
109Cited by
7References
3Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1988 |
| Grant date | Dec 26, 1989 |
| Priority date | — |
| Expiry date | Sep 8, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/163
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A subscription television system for distributing program material protected by copyright to subscribers comprises a transmitter including a data insertion circuit for inserting a control bit in a transmitted signal comprising other control data and the protected program material. A receiver of the system includes a memory for storing a pre-assigned subscriber identification. Upon receipt and identification of the control bit at the receiver, the receiver inserts the subscriber identification into the program material so that any unauthorized copy made of the program material may be found to include the subscriber identification.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.