Signalling system
US6850555B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 16, 1998 |
| Grant date | Feb 1, 2005 |
| Priority date | — |
| Expiry date | Jan 16, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J13/0022
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A signalling system is provided which can be used to update the prices of goods which are electronically displayed on supermarket shelves (1). The signalling system comprises a first signalling device having an input terminal for receiving electrical message data received from a central computer system (5), a spread spectrum encoder for encoding the received message data and an electroacoustic converter (11) for converting the encoded data into corresponding acoustic signals and for transmitting the acoustic signals into a transmission medium. The signalling system also comprises a second signalling device (3) having means for receiving acoustic signals from said transmission medium and for converting the received acoustic signals into corrresponding electrical signals, a spread spectrum decoder for decoding the received signals and a message regenerator for regenerating the message data transmitted by the first signalling device from the signals output by the decoder.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.