Radiocommunications equipment with a security calls mode, and extension unit forming part of such equipment
US6052576A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 7, 1997 |
| Grant date | Apr 18, 2000 |
| Priority date | — |
| Expiry date | Jul 7, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W12/06
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The equipment comprises a radio terminal adapted to calls with a public mobile telephony network supporting voice transmission channels and data channels, and an extension unit which can be connected to a data interface of the terminal and allowing calls on the data channels of the network. This extension unit comprises a microphone, an earphone, a vocoder and a ciphering module. It has the same external appearance as a conventional mobile radio terminal. In a security call mode, the signal coming from the microphone of the extension unit is processed by the vocoder and then by the ciphering module in order to produce data sent to the data interface of the terminal, and the data received from the data interface of the terminal are processed by the ciphering module and by the vocoder in order to control the earphone of the extension unit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.