System for card to card transfer of monetary values

A system for electronic transfer of monetary values comprising:

• first and second smart cards, each of the first and second smart cards comprising:
• a data storage device that stores data representing monetary values;
• control circuitry that controls the transfer of the monetary values into the data storage device and that controls the transfer of the monetary values out of the data storage device;
• and
• a first data transfer interface that couples directly by contact with a second data transfer interface on the other card to enable data to be transferred between the first and second cards to effect the transfer of monetary values from one of the cards to the other of the cards, wherein the first data transfer interface comprises a slot along an edge of the first smart card and wherein the data are transferred by sliding the second data transfer interface of the second smart card through the slot of the first smart card.