MMC Memory Guide

The MMC (MultiMediaCard) is a removable flash memory card. It was developed by Siemens AG and SanDisk, and first released in 1997. It measures 24mm x 32mm x 1.4mm (about the size of a postage stamp), and is available in sizes up to 4 GB. An 8 GB size has been announced but is not yet available. The MMC card is typically used in portable electronic devices such as digital cameras. Many newer computers now have SD slots, which can be used with MMC cards.

Since the introduction of the Secure Digital card, the MMC is far less popular. Few companies include an MMC slot in their device. But MMCs can be used in most devices which support SD cards so long as the software or firmware on the device supports them. They can be used in most devices which use memory cards, such as cellular phones, digital audio players, digital cameras and PDAs. although very few companies include an MMC slot in their devices, it's computability with the SD slot keep it useful in modern devices.

There are several variations of MMC (RS-MMC) cards. A reduced size MMC card is a 24mm x 18mm x 1.4mm version. They are availible in sizes up to 2 GB. There is a Dual-Voltage MMC card (DV-MMC), which supports an operating voltage of 1.8v and 3.3v. In 2005 two variations were introduced to compete against SD cards, MMCplus and MMCmobile. These support higher running speeds at 26MHz and 52MHz than the original MMC or the SD card. The MMCmicro is a very small (smaller than RS-MMC) card, measuring at 14mm x 12mm x 1.1mm. SecureMMC is intended to compete with SD cards and Memory Stick.