<p>Provided is a computer system in which power is supplied only when necessary and a CPU is stopped when an idling state continues for a predetermined period, thereby subjecting a system to power saving. The computer system consists of a plurality of combined units each comprising a communication means which receives enciphered data from a shop terminal through a network and deciphers the data; a memory means which stores the received data at a predetermined blocked fixed-address; a data processing means which calculates the data received from the shop terminal; and an externally controllable latch circuit which selectively controls the side to be connected with the memory means. The latch circuit maintains a state just prior to the disconnection of the power even when the power is disconnected.</p>
