Picture/audio signal transmission system
US4251691A · kind A · utility
118Cited by
2References
4Claims
0Family size
Assignees
Inventors
Key dates
| Filing date | Dec 1, 1978 |
| Grant date | Feb 17, 1981 |
| Priority date | — |
| Expiry date | Dec 1, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/085
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A center-to-end type information service system utilizing the public telephone networks that are fundamental communication media of nation-wide scale is disclosed in which desired information is requested from the terminal side to the center by means of a telephone set or simplified keyboard and then delivered to and received by a TV receiver. A part of the center functions is transferred together with the exchange function to a subcenter located near the terminal. Thus, the length of transmission path connecting the center to terminals becomes shorter and the cost of the whole system can be cut down.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.