DTMF signal detection apparatus
US5172406A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 31, 1990 |
| Grant date | Dec 15, 1992 |
| Priority date | — |
| Expiry date | Aug 31, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q1/46
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Apparatus for detecting and identifying DTMF signals in connection with a voice store and forward equipment (VSF) and for preventing talk-off, whether generated by the VSF or by a user of the VSF. In particular, the apparatus for use in connection with an interface which receives an analog signal from and applies an analog signal to a telephone line, the apparatus including: (a) detection means, responsive to an analog signal received from the interface, for detecting DTMF signals in the received analog signal and for generating DTMF indication signals in response thereto; (b) means for storing a representation of the received analog signal and at least some of the DTMF indication signals and for applying at least some of the DTMF indication signals to a decision means; and (c) means for retrieving a representation of an output analog signal and a representation of output DTMF indication signals and for applying them to the decision means; wherein the decision means is means for applying the output analog signal to the interface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.