An apparatus communicating with data systems and a method of communicating with data systems.

In an apparatus (10, 49) communicating with a high secrecy and high security on-line verification data system (40) and an off-line verification data system (18) of a lower secrecy and security level, a person in possession of a card (21, 22, 23, 24) inputs the card into the apparatus (10, 49). The data are read from the card and input to a security module (50) of the apparatus. On the basis of the data read from the card, the apparatus (10, 49) identifies the card as a card belonging to the on-line or the off-line data system. Within the security module (50), a keyboard (46) is arranged, on which the person in possession of the card inputs a personal authentification code into the security module. Provided the card has been identified as a card belonging to the on-line data system (40), the data read from the card (21) and the code input by means of the keyboard (46) are encrypted using an encryption algorithm stored in a first storage means of the security module (50) and are output to the on-line data system (40), within which the authenticity of the person in possession of the card is verified. Provided the card has been identified as a card belonging to the off-line data system (18), the data read from the card (22, 23, 24) are compared to the code by employing a verification algorithm, stored in a second storage means of the security module (50), in a comparator of the security module (50). As a result of the comparison within the comparator an authenticity code or, alternatively, a non-authenticity code is output to the off-line data system, exclusively.