MMC can be used in many devices that can use Secure Digital (SD) cards. MMC originally used a 1- bit serial interface, but newer versions of the specification allow transfers of 4 or 8 bits at a time.
MMC is about the size of a postage stamp: 24 mm × 32 mm × 1.4 mm. Both products were initially introduced using SanDisk NOR-based flash technology. Unveiled in 1997 by SanDisk and Siemens, MMC is based on a surface-contact low pin-count serial interface using a single memory stack substrate assembly, and is therefore much smaller than earlier systems based on high pin-count parallel interfaces using traditional surface-mount assembly such as CompactFlash. The MultiMediaCard, officially abbreviated as MMC, is a memory card standard used for solid-state storage.
