Abstract: An optical fibre for propagating a signal in different modes, including a longitudinal length “a” of a change in the tension buildup in the optical fibre and a longitudinal distance “L” between two such changes are in accordance with the equation, a<=0.5 L, for at least part of the optical fibre.

Abstract: There is provided an electronic system (10) for providing visible user physical feedback via at least one data token (80). The system (10) includes a computing means (50), a data store (40) coupled to said computing means (50) for at least one of inputting data and outputting data content from the store (40), and a token interfacing means (60, 70) coupled to said computing means (50) for interfacing to said at least one data token (80) detachable from the system (10), said at least one token (80) for representing data content in the store (40).

Abstract: This invention relates to a method (and a corresponding terminal) of detecting a presence of a circuit extending arrangement inserted between a physical interface, connected to a terminal, and a smart card, the physical interface being adapted to receive the smart card, the method comprising the steps of measuring at least one electrical characteristic of the physical interface, and determining whether a circuit extending arrangement, changing at least one characteristic of said physical interface, is coupled to said physical interface on the basis said measurement. In this way, simple and efficient detection of a tampering/spy circuit is provided.