A controller to which a second controller is connected arranges, based on predetermined integrated scenario information defining a first input region allotted for the controller and a second input region allotted for the second controller within data regions for packet input data, operation input data corresponding to an operation input from a user in the first input region, and data based on extended input data obtained from an extension apparatus in the second input region, generates packet input data, and transmits it to a device main unit.