Abstract: A data combination card is provided which includes a thin electrically non-conductive, non-metallic substrate. A thin layer of metal is secured to a portion of one side of the substrate. Holes are selectively formed in the metal layer in data positions which, when taken together with the remainder of the metal layer, constitute binary coded information. The substrate is folded over upon itself to provide a composite coded card with the metal layer between two outer layers of the substrate. The card is adapted to be inserted into a card reader housing which contains a protrusion extending into the card reader housing to prohibit access to that portion of the housing. Discrete sensing means are mounted in the card reader housing to detect the presence or absence of an adjacent metal area. The card reader receives the card in a manner to position the metal layer adjacent the sensing means.