[Problem] To reliably perform charge/discharge control in a charge/discharge system comprising a charger/discharger and a battery system that includes a secondary battery and a battery-side control device. [Solution] The battery system 100 including the secondary battery 110 and the battery-side control device 120, and a discharger 200 configured to discharge the secondary battery 110 to output direct-current power and convert power from the alternating-current power supply 4 into direct current to charge the secondary battery 110, are included; the charger/discharger 200 includes a charge/discharge-side control device 210 configured to control charge and discharge; and when the charge/discharge-side control device 210 establishes communicable connection with the battery-side control device 120, and receives specific information for specifying a charge/discharge control program, which is a program for controlling the charge and discharge transmitted from the battery system 100, the charge/discharge-side con
