The 1541-III is a PIC microcontroller controlling an FAT16 MMC/SD card with .D64 files. It is connected to the Commodore via the standard IEC bus. The circuit as a whole behaves like a 1541 disk drive (therefore the name 1541-III). It has been successfully tested on the following machines: VIC 20, C64, C16, Plus4 and the DTV.