PURPOSE: To set up all slave machines in polling bits corresponding to the set number of slave machines and to reset machines succeeding the inputted number of slave machines by setting up the number of plural slave machines connected to a control machine through a common like in a polling table.

CONSTITUTION: Electronic cash registers (ECRs) consist of a control station ECR 10 and plural slave station ECRs 11 and the slave station ECRs 11 are connected to the control station ECR 10 through common like 12. A CPU 13 executes various processing based upon a program stored in a ROM 14. A RAM 15 to be used for recording/reading out necessary data has a polling table. A polling table setting program for setting up all slave station ECRs 11 to driven states and setting up slave stations of driving ECRs 11 to driven states and setting up slave stations in polling bits succeeding the input of units to undriven states is prepared. Consequently the setting of the polling table can simply be executed within a short time and the slave stations can easily be managed.