Abstract: A sales data processing system reads sales data containing article codes previously attached to sales articles, and executes registration of sales data according to the sales data thus read.

Abstract: A memory pack is provided having a random access memory connected between a positive power source terminal and a ground terminal, an addressing terminal coupled with the random access memory, and a data input/output terminal coupled with the random access memory. The memory pack further includes an LED energizing terminal, a light emission element which is connected between the LED energizing terminal and a positive power source terminal, the LED being lit by an energizing signal applied to the LED energizing terminal, a RAM energizing terminal and a photocoupler which is connected between the RAM energizing terminal and the random access memory and which responds to an energizing signal applied to the RAM energizing terminal to apply an output signal to the random access memory thereby to set the random access memory to be operative.

Abstract: An electronic cash register is provided which comprises a keyboard including a plurality of entry keys, function keys and department keys, a memory, a first interface circuit with which a cashier memory pack is mechanically, electrically and disconnectably coupled, a second interface circuit with which a terminal memory pack is mechanically, electrically and disconnectably coupled, and a central processing unit connected to the keyboard, the memory, and the first and second interface circuits in which the sales information generated upon depression of the entry keys, the function keys and department keys are loaded into the memory and at least the sales total for a customer in the sales information is loaded for each transaction into the cashier memory pack and the terminal memory pack.

Abstract: A data processing apparatus for an electronic cash register comprises a keyboard having a plurality of entry keys, a printer, a memory unit, an interface circuit with which a memory pack storing sales data is mechanically, electrically and removably coupled and a data processing unit connected with the keyboard, the printer, the memory unit and the interface circuit. Responding to operations of one of the keys for sales data selection, the data processing unit energizes the memory pack connected to the interface circuit to read out the sales data corresponding to the operated sales information key from the energized memory pack and write the read-out sales data into the memory unit and then issue a print signal to the printer for printing the sales data.