Signalling system and a transponder for use in the system
US6925287B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 4, 2002 |
| Grant date | Aug 2, 2005 |
| Priority date | — |
| Expiry date | Apr 20, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/0723
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A signalling system includes a plurality of active transponders (10), an interrogation station (12) and a source (14) of switching signals. Each of the transponders has a microcontroller (20), a radio transceiver (34) for responding to radio interrogation signals from the interrogation station, the radio transceiver being coupled to the controller by way of switching means (36) which switches the transceiver on or off whilst leaving the microcontroller active, and a passive receiver (38) for receiving switching signals from the source of switching signals which signals are used by the microcontroller for switching-on or -off the transceiver. Transducers (26, 28, 30) may be coupled to the microcontroller for monitoring environmental features, such as ambient temperature and humidity, and data relating to the features is stored in a RAM (32) in readiness to be relayed to storage means (56) in the interrogation station (12) as and when required. Signals received by the passive receiver enable the radio transceiver to be de-activated in locations, such as in an aircraft, where spurious radiation from the transponder is not permitted and to be re-activated when removed from such a locat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.