Abstract: A proceeds processing apparatus has an apparatus body, and a keyboard and a card reader provided on the apparatus body for entering first data indicative of the contents of a transaction. An operation control is accommodated in the apparatus body for executing data processing including proceeds processing by performing arithmetic operations with inputted data. A display and a printer are provided on the apparatus body and interconnected to the operation control for outputting the result of data processing. A customer-oriented input unit has a keyboard and a control for inputting second data for determining whether or not the first data entered are agreed to. An interface and a cable electrically interconnect the keyboard and the control to the operation control. The operation control determinines, in response to the second data fed from the keyboard and the control, whether or not the first data are agreed to on the basis of the second data and feeds a result of decision to the display and printer.

Abstract: An IC card reader/writer has frequency mode identifying means for determining whether or not an IC card loaded thereon has an identifiable frequency. When the frequency mode of the IC card is identifiable, clock frequency determining means reads frequency data representative of an operating clock frequency out of the IC card to determine an operating clock frequency particular to the card. Based on the determined operating clock frequency of the IC card, frequency setting means converts reference clock pulses being generated by reference clock generating means into clock pulses which match the clock frequency of the IC card, and feeds those clock pulses to the card. The reader/writer is capable of producing clock pulses the frequency of which is variable in matching relation to the frequency of operating clock pulses of an IC card.

Abstract: An IC card reader/writer has a short-circuit detector for determining, when an IC card is inserted in the reader/writer, whether or not any of connecting terminals for feeding a current to the IC card is short-circuited, and producing a resultant signal representative of the result of determination. A control is responsive to the resultant signal for performing, when the resultant signal does not indicate short-circuit, control such that the current is fed to the IC card via the connecting terminals. A reference voltage generator generates a reference voltage, while the short-circuit detector determines whether any of the connecting terminals is short-circuited or not by using the generated reference voltage.