@spruce_m00se for using tons of db9 controllers i recommend either a vision-daptor or ultimate pc interface (upci is 2player version. Has some other controllers the vision-adapter doesnt have. Both made by the same person.) The master system also has the two extra pins as functiong buttons. They match the same button numbers as start and mode button on the genesis mode. He added these so i could use my db9 modified nes and turbografx/pc engine controllers. He makes some other controller adapters too. His adapters truly are the best i have ever used.