Data transfer system and data transfer terminal device

A financial transaction data processing system comprising:

• a plurality of host bank computers operatively maintained by a plurality of banking institutions and each containing account information denoting money balances of plural host bank accounts;
• a communications network interconnecting said plurality of host bank computers;
• a plurality of automated teller machines operatively maintained by the plurality of banking institutions and connectable to said plurality of host bank computers so as to access said account information to transfer money to and from said plural host bank accounts;
• a transaction terminal device detachably and operatively connectable to at least one of said plurality of host bank computers, said transaction terminal device having two IC card insertion slots;
• and
• a plurality of portable IC cards each containing a non-volatile IC chip memory for storing a carrier money balance and each insertable into at least one of said plurality of automated teller machines and into one of said IC card insertion slots of said transaction terminal device;
• wherein each of said automated teller machines includes means, responsive to the insertion therein of one of said portable IC cards and to input instructions, for effecting a first transaction by deducting a first specified amount of money from the balance of a designated host bank account of a connected one of said host bank computers and adding the first specified amount to the carrier money balance of said one of said portable IC cards;
• wherein said transaction terminal device includes at least one manipulation key for specifying a second specified amount of money, transfer means, responsive to the insertion of two of said portable IC cards into said IC card insertion slots and to input instructions, for effecting a second transaction by deducting the second specified amount of money specified by said at least one manipulation key from the carrier money balance stored in the IC chip memory of a first of said two portable IC cards and adding the second specified amount of money to the carrier money balance stored in the IC chip memory of a second of said two portable IC cards, a memory for storing data relating to said second transaction, and transmitting means for transmitting second transaction verification data indicative of the second transaction from said memory to a connected one of said plurality of host bank computers;
• wherein one of said automated teller machines further includes means, responsive to the insertion therein of said second of said portable IC cards and to input instructions, for initiating a verification process in which an amount of the carrier money balance of said second of said portable IC cards is verified with reference to said second transaction verification data transmitted to the connected one of the plurality of host bank computers by said transaction terminal device and, thereafter, if said second transaction verification data has been transmitted to said connected host bank computer, for effecting a third transaction by adding a third specified amount of money to a designated host bank account of a connected host bank computer and deducting the third specified amount from the carrier money balance of said second of said portable IC cards;
• and
• wherein, when said second of said portable IC cards is inserted into said one of said automated teller machines before said second transaction verification data has been transmitted to said connected one of the plurality of host bank computers by said transaction terminal device, said third transaction is effected after said second transaction verification data has been transmitted to said connected one of the plurality of host bank computers by said transaction terminal device.