Packet data communication system
US5479441A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 18, 1994 |
| Grant date | Dec 26, 1995 |
| Priority date | — |
| Expiry date | Jan 18, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2001/0093
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A packet data transmission system is used to link a number of remote hand-held data-gathering units such as bar code readers to a central computer which maintains a database management system. Data packets are sent from the remote units by an RF link to intermediate base stations, then sent by the base stations to the central computer by a serial link. Direct sequence spread spectrum modulation is used for the RF link. The remote hand-held units initiate an exchange using RF transmission to and from the base stations, receiving only during a rigid time window following a transmission from the remote unit. The base stations cannot initiate communication to the remote units, but instead send data to the remote units only as part of the exchange.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.