again by the effect of elasticity of the reeds by orienting the reed switches perpendicular to one another they are less likely to be simultaneously closed by any magnetic field from a more distant source suitable ultra miniature reed switches having an outside diameter of 0 075 inches are available from aleph international san fernando calif 91340 it should be noted that magnetically operated switches may be formed from components which are an integral part of the mechanical and electrical structures of the card thereby reducing cost by eliminating the need to procure and assemble individual switching components such as reed switches a still further embodiment of the invention shown in fig8 of the drawings employs capacitive coupling between a pattern of thin film conductors on the card 801 and a corresponding pattern of conductors on a key 850 the pattern on the card includes three pairs of adjacent semicircles seen at 861 862 and 863 the key 850 is formed on non conducting material and carries three conductive disks 871 872 and 873 when the key 850 is properly positioned flush against the surface of the card 801 with the disks 871 872 and 873 aligned with the patterns 861 862 and 863 respectively each disk on the key capacitively couples each pair of semicircular patterns on.