ISDN-based system for making a video call
US5371534A · kind A · utility
151Cited by
2References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 23, 1992 |
| Grant date | Dec 6, 1994 |
| Priority date | — |
| Expiry date | Jul 23, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2213/392
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A single medium (audio) voice grade call initiated by an ISDN video phone and directed to another ISDN video phone is converted into a multimedia (audio and video) ISDN call by a) maintaining the connection for the voice grade call while the ISDN audio and video connection is being established over a bearer channel of the ISDN subscriber loop different from the bearer channel being used by the voice grade connection, b) switching the audio signals from the voice grade call to the ISDN audio and video connection, once the ISDN audio and video connection is established, and c) tearing down the initial voice grade call.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.