Robust DTMF detection in an unreliable voice-over-IP (VoIP) environment
US9401998B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 2012 |
| Grant date | Jul 26, 2016 |
| Priority date | — |
| Expiry date | Feb 11, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/5158
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method to discriminate a signal as a DTMF digit is operative in a service provider having a VoIP-based media server. The media server accepts both in-band DTMF and RTP telephone events. A digit detection module receives as input a data stream that may include one or more DTMF digits. The module processes the input data stream and provides, as output, an indication of what digit(s) have been detected and from what source (e.g., in-band audio, an RTP 2833 telephone event, of both). The output is then further processed by a discrimination algorithm to make a final digit determination. If RTP telephone events are detected, the algorithm prefers them and ignores in-band DTMF until the call ends or the media is re-negotiated. The approach detects when duplicate digits of differing types are initially received and only accepts one of them, regardless of spacing or duration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.