SD Cards
SD stands for Secure Digital. The SD card isn’t the only memory card standard approved by the Secure Digital Card Association. Other SD Card formats include miniSD, microSD (formerly known as TransFlash Card)
These smaller mini SD and micro SD cards are usable in full size MMC, SD, SDIO slots if used with an adapter.
Standard SD card capacities range from 4 MB to 4 GB.
SD Cards are usually only available from 4MB to 2GB, but some manufacturers have produced 4 GB SD cards that conform to neither the SD2.0/SDHC spec or existing SD devices.
As SD slots still support MMCs, the separately-evolved smaller MMC variants are also compatible with SD supporting devices. Unlike miniSD and microSD, RS-MMC slots maintain backward compatibility with full-sized MMCs, because the RS-MMCs are simply shorter MMCs.
microSD (Micro SD, Transflash, T-Flash card) is a format for removable flash memory cards. It is normally used in mobile phones, handheld GPS devices, portable media players (MP3 players), digital audio players, expandable USB flash memory drives, for Nintendo DS flashcards and digital cameras.
TransFlash and microSD cards are the same (each can be used in devices made for the other), except that micro SD adds support for SDIO mode and Trans flash does not.
