Page selection device for videotext system
US4308558A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 22, 1980 |
| Grant date | Dec 29, 1981 |
| Priority date | — |
| Expiry date | May 22, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/0882
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A page selection device for a videotext system in which the incoming data are arranged in blocks comprising a data group following a prefix, some of the blocks having within said group specific codes called page headers, a page comprising the data between a page header and an end of page code, the page to be displayed being transferred to a page memory, said device comprising an input buffer having a capacity of at least one block, in which data are entered as they appear, an additional buffer with a capacity of at least one block, in which the incoming data are only entered if a page header has been detected, a main buffer with a capacity of at least one page, in which the content of the input buffer is transferred when a page header is detected, and means for comparing the page number entered in the additional buffer with the selected number and for controlling, according to whether the comparison is positive or not, either reading of the data entered in the main buffer for transfer to said memory or resetting to zero the additional and main buffers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.