Abstract: A system is disclosed for incorporating a security feature in a PCMCIA memory card or like instrument for protecting information contained in electrical signals being exchanged through the PCMCIA card between a source card containing the information, e.g., a smart IC card, and a computer in which the information is used. PCMCIA cards are accomodatable in a special input slot in laptop or notebook type computers having an I/O interface that cooperates with a similar interface on an edge of the card. The interface is coupled, for transferring signals to and from the computer, to a PCMCIA chip in the card, which chip may also be coupled to a card reader having an I/O contact portion on another edge for mating with the edge of a smart card to transfer signals there between and to and from the interface to the laptop or notebook.