The new model control box SC-921 and SC-922 have been newly developed. The control boxes are resistant to voltage fluctuations, noise, and vibration. The new model control boxes are provided with an energy-saving mode for the first time in a control box for sewing machines. Power consumption during standby periods is further reduced. Considering convenience in setup and resource saving, both the volume and the weight of the control box has been reduced by 30% or more (as compared with the conventional control box SC-500 and SC-510).