Method and system of communication for a non-contact IC card
US5113184A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 20, 1991 |
| Grant date | May 12, 1992 |
| Priority date | — |
| Expiry date | May 20, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10336
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A data communication system includes an external unit, such as a card reader/writer, with the ability of reading and writing data for a recording medium. The recording medium, such as an IC card, transacts signals with the external unit by being coupled electromagnetically in non-contact fashion with the external unit and is supplied power from the external unit. The external unit includes a first data processor, a first electromagnetic transducing coil for the electromagnetic coupling with the medium, a carrier wave generator connected to the first coil for generating a carrier for transmitting a signal to the recording medium, and a received signal discriminator. The recording medium includes a second data processor, a second electromagnetic transducing coil for the electromagnetic coupling with the external unit, a switching circuit connected to the second coil for varying the load impedance of the second coil in response to a signal to be sent to the first coil, and a received signal detecting circuit. The data signal from the recording medium is demodulated for the carrier frequency from the external unit in response to the data signal, and transmitted to the external unit. Th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.