A system for use in assisting a self-service transaction at a service facility includes one or more self-service terminals, each configured to gather transaction information associated with a customer who is engaged in a business transaction with the service facility through the self-service terminal. Variable impedance power supply line and variable impedance ground line supplying voltages VCL2 and VSL2, respectively, are set to a high impedance state in the stand-by cycle, and low impedance state in the active cycle and in the row related signal reset time period. The main data includes first data of a first memory cell of the selected memory cell row and second data of a second memory cell of the selected memory cell row.