1 and v 52 are reserved in the pc card specification the present invention utilizes one of these reserved combinations of cd 1 cd 2 vs 1 and vs 2 and additionally uses a status change signal stschg to indicate whether a smart card has been inserted into the slot either directly or via an adapter the status change signal is preferably used in the present invention since this signal is not utilized during the detection process for conventional pc card cards and is only used once the card type is known thus in one sense the smart card sensing logic 30 a shown in fig3 can be viewed as a state machine that determines the type of card inserted into a socket to that end and referring to fig4 a state machine representation of the card sensing logic 30 a of fig3 is depicted as is shown the card sensing logic 30 a accepts as inputs cd 1 cd 2 vs 1 v 52 and status change labeled 40 42 44 46 and 48 respectively in accordance with the reserved arrangement of cd 1 cd 2 vs 1 v 52 as shown in fig5 and the addition of the status change signal the state machine 30 a determines the appropriate logic 32 a for communicating with the 4 given type of card for example certain combinations of cd.