PURPOSE: To perform a fault countermeasure smoothly by separating a display part from communication with a POS main body when abnormality exists in out-fitted equipment, and displaying the abnormality of an input/output part other than the display part on th display part.

CONSTITUTION: A control means 4, when deciding the abnormality of the display of the out-fitted equipment out of the out-fitted equipment 2 exists, separates the out-fitted equipment 2 from the communication with a point of sales information manaing (POS) main body 1. On the other hand, the control means 4, when deciding that the abnormality exists in the input/output parts 12, 13, 15 other than the display part 14 of the out-fitted equipment 2, displays the fact of the abnormality of the input/output parts 12, 13, 15 on the display part of the out-fitted equipment 2. Therefore, it is possible to perform the fault countermeasure can be performed smoothly even when the fault occurs is part of the out-fitted equipment connected to the POS main body 1, and to suppress influence on every kind of job to a minimum. In such a way, inconvenience such as interruption of the job of a service station and the lowering of customer service, etc., can be prevented occurring.