MultiMediaCard

A flash memory card that provides storage for cellphones, PDAs and other handheld devices. Introduced in 1997 with a 4MB capacity, the 32x24x1.4mm card weighs less than two grams. By 2005, storage increased to 2GB. The card uses flash memory for read/write applications or ROM chips (ROM-MMC) for static information, the latter widely used for adding applications to a Palm PDA.

One-time programmable (OTP) versions of the card are also available. MultiMediaCards (MMCs) are noted for their high transfer rates, up to 52 MB/sec. For more information, visit the MultiMediaCard Association at www.mmca.org.

Secure Versions
Two secure versions of the MultiMediaCard are offered. SecureMMC for Content Protection is used for copyrighted material. It contains encrypted content in readable flash memory and licensing information in a hardware-protected, tamper proof part of the card. SecureMMC for M-Commerce is a high-level security card for e-commerce transactions.

MMC and SD Cards
MultiMediaCards and SD Memory Cards share the same footprint, but MMCs are thinner and have only seven pins compared to nine. MMC cards can be read in SD Card readers, but SD Cards cannot be read in readers designed for MMC only.

Reduced-Size MMC
The RS-MMC card is approximately half the size of the full MultiMediaCard. Having the same width and thickness, RS-MMC measures 18mm from top to bottom instead of 32mm. With capacities of 1GB as of 2005, RS-MMC cards can be pushed into an adapter and plugged into full-size MMC slots. See SD Card.

MMC Vs. SD

MMC and SD Cards look the same except that MMCs are thinner (1.4mm vs. 2.1mm) and have seven pins for compared to nine on the SD. Card reader MMC/SD slots support both formats.

MMC Vs. RS-MMC

The reduced-size card can be pushed into an adapter and plugged into a full-size MMC slot.