The Yamaha DX7S Data ROM cartridge contains the factory soundset for the DX7S, including 64 voices, 32 performance memories, micro-tunings, and system setups. It’s used to restore the keyboard to its original presets or to reload missing factory patches. Loading requires disabling memory protection, selecting the cartridge bank, transferring the data, and re-enabling protection. Ideal for bringing a DX7S back to full factory spec.