PURPOSE: To omit a parameter by storing the inputted parameter added to a command inputted to control an exchange in a centralized maintenance operation center and adding the parameter inputted at the preceding input for the omission of the parameter.

CONSTITUTION: The maintenance operation center 1 is provided with an input parameter registration omitting means 100, which stores a prescribed input parameter such as an opposite station name designating the object exchange 2 and a pass word added to the input command to the control object exchange 2, extracts the input parameter already stored when the preceding command is inputted and adds the extracted parameter to a command whose parameter is omitted.