Patent ID: 7185110

Claim:
A data exchange system comprising at least one portable data processing unit ( 5 ) comprising data communication means ( 14 ), processing means ( 15 ) and memory means ( 16 ), the memory means ( 16 ) comprising an executive program ( 17 ) and at least one interaction context ( 19 ( 1 ) . . . 19 (m)) containing the following coherent data structure: a. a set of basic communication primitives (A( 1 ) . . . ) which are accepted whenever the data processing unit ( 5 ) communicates with a similar unit ( 4 ), said primitives at least including a primitive used to selectively enter one of the said interaction contexts ( 19 ( 1 ) . . . ); b. a set of procedural descriptions (C( 1 ) . . . ) defining the actions to be performed in response to each of the accepted communication primitives (A( 1 ) . . . ), at least comprising a first procedural description to be performed upon activating the interaction context, and a last procedural description to be performed immediately before deactivating the context; c. a, possibly empty, set of data elements (H( 1 ) . . . ) either permanently stored or computed, which are available for use when procedures as defined in the procedural descriptions (C( 1 ) . . . ) are performed; d. a, possibly empty, set of references to data elements, which references are associated to the procedural descriptions (C( 1 ) . . . ), said data elements are also accessible to possibly further interaction contexts and are available for use when procedures as defined in the procedural descriptions (C( 1 ) . . . ) are performed; e. a, possibly empty, data list comprising a list of references (B( 1 ) . . . ) to data elements which are available for explicit reference as part of a communication primitive (A( 1 ) . . . ) to be used by the procedural description (C( 1 ) . . . ) associated with the communication primitive; f. a set of access conditions associated to the data elements which are referenced in association to the procedural descriptions (C( 1 ) . . . ); g. a set of access conditions associated to the list of data references (B( 1 ) . . . ) in the data list.