Mobile radio data communication system
US4247947A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 25, 1979 |
| Grant date | Jan 27, 1981 |
| Priority date | — |
| Expiry date | Sep 25, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/40
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A mobile radio data communication system in which portable radio terminal units transmit a carrier wave modulated with various data and a stationary radio unit demodulates the modulated carrier wave into the transmitted data is disclosed. The data may relate to such aspects of business activities as production, inventory and sale, and are transmitted as analog speech signals. In order to transmit data, the operator presses a transmission key which causes a preamble digital signal and a terminal number digital signal to be successively transmitted. The operator, while pressing the transmission key, speaks into a microphone contained in the portable radio terminal unit. At the stationary radio unit, the preamble digital signal is recognized and the terminal number digital signal is temporarily stored. The transmitted analog speech signals are supplied to a speech recognition circuit which generates a digital speech signal that is stored in a memory. The stationary radio unit then generates a preamble digital signal which is transmitted followed by the temporarily stored terminal number digital signal and the digital speech signal. The portable radio terminal unit corresponding to the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.