Special services teletext communications system
US4393404A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 26, 1981 |
| Grant date | Jul 12, 1983 |
| Priority date | — |
| Expiry date | Feb 26, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/03
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A teletext communications system includes a transmitter cyclically transmitting a plurality of conventional teletext encoded data rows together with one or more teletext encoded special services data rows. A plurality of teletext decoder equipped receivers are operable for acquiring the conventional teletext rows but not the special services rows. Subscribers to the special services data are provided with data decoders responsive to the cyclical transmissions for acquiring only the special services data rows, the data decoders including apparatus for storing the data encoded in an acquired special services data row and for providing a display of the information represented thereby.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.