Three-way call detection using steganography
US7826604B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 24, 2007 |
| Grant date | Nov 2, 2010 |
| Priority date | — |
| Expiry date | Mar 12, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/665
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Three-way call detection is an important component of correctional facility telephone equipment because it helps restrict calling access by certain persons to certain restricted telephone numbers. Various three-way call detection methods exist, but all of these implementations suffer from one major limitation—the detection accuracy is not as high as is desired by the industry. The present invention improves detection accuracy, using “steganography.” Steganography involves hiding one set of data or signals within another signal or carrier in such a way that its presence is virtually imperceptible to the end recipient, and potential even the originator of the carrier signal. Television producers use steganographic methods to encode data in video signals for security, distribution monitoring, piracy-control, and other reasons. The present invention involves a device that connects to a telephone, either at the line or handset interfaces, and produces a known signal that is steganographically hidden within the user's normal voice signal. Detection equipment, residing at another location, monitors signals on telephone calls and tests for the presence of the hidden signal or data generate…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.