23. A smart card, comprising:

a microprocessor and associated memory; and

22. A user card transaction system, comprising:

21. The interface device of claim 18 wherein said plurality of contacts further include a clock signal contact in addition to said predefined set of contacts for providing a data clock signal from one of said peripheral devices.

United States Patent 6,199,128 Inventors: Sarat; Jean-Marc (Belmont, CA)

20. The interface device of claim 18 wherein said plurality of contacts further include a mode contact which provides a signal that identifies whether the smart card is to operate in accordance with said operating protocol or a different protocol to communicate with said peripheral devices.

United States Patent 6,199,128 Inventors: Sarat; Jean-Marc (Belmont, CA)

19. The interface device of claim 18 wherein said operating protocol conforms to an ISO standard for smart cards.

United States Patent 6,199,128 Inventors: Sarat; Jean-Marc (Belmont, CA)

18. An interface device for use with a smart card having first and second data input/output contacts, comprising:

17. The smart card of claim 13 wherein said plurality of contacts further include a clock signal contact in addition to said predefined set of contacts for receiving a data clock signal from one of said peripheral devices.

United States Patent 6,199,128 Inventors: Sarat; Jean-Marc (Belmont, CA)

16. The smart card of claim 13 wherein said plurality of contacts further include a mode contact which receives a signal that identifies whether said microprocessor is to operate in accordance with said operating protocol or a different protocol to communicate with said peripheral devices.

United States Patent 6,199,128 Inventors: Sarat; Jean-Marc (Belmont, CA)

15. The smart card of claim 13 wherein said operating protocol conforms to an ISO standard for smart cards.

United States Patent 6,199,128 Inventors: Sarat; Jean-Marc (Belmont, CA)

14. The smart card of claim 13 wherein said microprocessor selectively provides a data communication path between said two data input/output contacts to enable said first and second peripheral devices to communicate with each other or only with said user card.

United States Patent 6,199,128 Inventors: Sarat; Jean-Marc (Belmont, CA)