Video-telephone system initially signifies caller to called subscriber
US3946158A · kind A · utility
Inventors
Key dates
| Filing date | Apr 25, 1975 |
| Grant date | Mar 23, 1976 |
| Priority date | — |
| Expiry date | Apr 25, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/575
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Improvement to video-telephone systems allowing a called subscriber to have at his disposal on his television receiver screen, before he takes off his handset, information about the person who has initiated the call. Each subscriber station has a handset, a television camera, a television receiver and a character generator and is connected to a switching network by a telephone line, an incoming video line and an outgoing video line. Means are provided in the calling station for connecting to the outgoing video line the character generator when the calling subscriber takes down the handset and the television camera when video signals are detected on the incoming video line and in the called station for supplying with current the television receiver when ringing tone signals are detected on the telephone line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.