PURPOSE: To ensure effective transactions by using a means which checks whether an identification number of a customer is recorded or not to a transaction medium.
CONSTITUTION: A control center 1 is connected to a cash dispenser (CD) 2 via a MODEM 3 and a terminal controller 4. If a transaction medium put into the CD 2 contains no identification number, an identification number is received from the center 1 and compared with the number supplied from a customer. When coincidence is obtained between both numbers, the transaction medium is returned to the customer. If not, the transaction medium is collected.