Public telephone clip-on fraud prevention system
US5930345A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1997 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | May 20, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M2215/0148
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
To prevent so-called "clip-on" fraud from occurring at a public telephone station, such as a coin operated public telephone, a unique signature identifier is transmitted at the telephone following the transmission of the dialed number. If remote equipment determines that the expected identifier is not correct, or it fails to receive the signature, then the remote equipment terminates the call. Once the call is completed, then the public telephone is expected to periodically transmits a second identifier. The completed call may also be terminated if the remote equipment does not receive the expected second identifier at an expected rate or if a received second identifier is not correct.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.