Method and apparatus for detecting an attempted three-way conference call on a remote telephone
US5539812A · kind A · utility
Inventors
Key dates
| Filing date | Nov 8, 1994 |
| Grant date | Jul 23, 1996 |
| Priority date | — |
| Expiry date | Nov 8, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M2203/5018
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus for use in connection with a telecommunication between a local telephone and a remote telephone, which are capable of detecting whether one of the parties to the communication has attempted to initiate a three-way, i.e., conference, call by using a hook-flash signal. The apparatus includes a low pass filter for passing energy having frequencies below about 500 Hz, and an energy detector for detecting a specific electrical energy pulse characteristic of the hook-flash having passed through the low pass filter. The existence of the hook-flash is confirmed by digital signal processing equipment which identifies a rapid drop-off in energy also characteristic of the hook-flash signal. Optionally, the hook-flash may be further confirmed by including software for cooperating with the energy detector to ascertain whether sound has occurred in the telecommunication during a predetermined period following the first hook-flash signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.