Voice mail system with improved detection and cancellation
US4885763A · kind A · utility
17Cited by
45References
1Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 1, 1987 |
| Grant date | Dec 5, 1989 |
| Priority date | — |
| Expiry date | Dec 1, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/533
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A voice mail system includes method and apparatus for muting a previously recorded audio signal upon detection of a DTMF signal to differentiate between recorded DTMF signals and valid DTMF commands. A DTMF signal detected after muting is recognized as an invalid command.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.