Pulse or digital communications – Miscellaneous
Reexamination Certificate
1998-02-25
2001-03-20
Vo, Don N. (Department: 2631)
Pulse or digital communications
Miscellaneous
Reexamination Certificate
active
06205194
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a device for communicating with a portable data medium in a communication using at least a power signal supplied by an electric energy source, a control signal and a data transmission signal.
2. Description of Related Art
Typically, the portable data medium can be a chip card incorporating a microprocessor or microwired logic circuits defining areas to which access is controlled and thus capable of containing secret information such as cryptographic keys (see for example the portable object described in U.S. Pat. No. 4,211,919).
The object of the invention is to offer an original solution for solving the general problem of the sequencing of the signals, particularly so as to comply with the standards applicable in this case (for example ISO standard 7816-3). It makes it possible, in a simple way, to meet the contradictory requirements of detecting the interruption of the power signal if the portable data medium is removed, and of continuing to supply this signal to the portable data medium for a given time after this detection.
SUMMARY OF THE INVENTION
For this purpose, the device according to the invention comprises: interrupting means disposed between the electric energy source and the portable data medium and controlled by the latter so that they interrupt the supply of the power signal to the portable data medium from the electric energy source if the portable data medium is not cooperating with the device and so that they allow this supply if the portable data medium is cooperating with the device;
energy storage means designed to store the electric energy received from the electric energy source, connected to a power supply input of the portable data medium so as to supply this power signal to the latter for a predetermined time following an interruption of this supply of the power signal from the electric energy source;
data processing means designed to ensure transmission to the portable data medium of the signals according to a predetermined sequencing, and to interrupt this transmission according to a predetermined sequencing, as well as to detect the interruption of the supply of the power signal from the electric energy source, then trigger the interruption of the other signals according to this predetermined sequencing while the power signal is supplied from the energy storage means.
REFERENCES:
patent: 5379435 (1995-01-01), Hanaoka
patent: 5408421 (1995-04-01), Prest et al.
CP8 Transac
Kondracki Edwards J.
Miles & Stockbridge P.C.
Vo Don N.
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