Configurable parameter DTMF detector
US5163050A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 23, 1991 |
| Grant date | Nov 10, 1992 |
| Priority date | — |
| Expiry date | Jan 23, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q1/457
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a digital messaging system (10), an apparatus (37) and method for determining whether a DTMF (Dual Tone Multi Frequency) digit is present on an input signal (11,12). A heuristics engine (37) performs a series of tests on the input signal (11,12) using a set of parameters that are stored in a RAM (38). There is one parameter for each of a set of input signal (11,12) characteristics and for each of a set of operating modes of the digital messaging system (10). All of the parameters are configurable. The configurability allows for the use of non-standard telephone equipment (13,14) and minimizes deleterious effects such as talkoff. The tests are from the set of sets comprising an absolute magnitude test, a frequency deviation test, a twist test, an echo test, a consistency test, and a temporal test.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.