SD card memory card is an independent storage medium used in mobile phones, digital cameras, portable computers, MP3 and other digital products. It is generally in the form of a card, so it is collectively called "memory card", also called "digital memory card", "Digital memory card", "memory card", etc. Secure Digital card is referred to as SD card. Literally, this card is a security card. It is better than CF card and early SM card in terms of security performance. It is a brand-new memory card product jointly developed by Japan's Panasonic Corporation, Toshiba Corporation and Corporation. SD cards can be seen in many ways as an upgrade to MMC. Both look and work the same way, except that the MMC card is slightly thinner, but any machine that uses an SD card device can use the MMC card. Full name: TransFLash, jointly developed by Motorola and SANDISK, launched in 2004. It is an ultra-small card (11*15*1MM), which is about 1/4 of the SD card, and can be regarded as the smallest memory card at present. TF card can be used as SD card after SD card converter. The adapter can be used on devices that use SD as a storage medium. TransFlash was primarily developed for camera phones to capture large images and to be able to download larger video clips. TransFlash cards can be used to store personal data, such as digital photos, MP3s, games, applications and personal data for mobile phones, etc., and a copyright protection management system is set up to protect downloaded music, images and games; new models to be launched in the future TransFlash also features encryption to protect personal data, financial records and health and medical documents. The compact size of TransFlash allows manufacturers to adopt this design without worrying about the size of the phone, and another flexible application is that suppliers can make replacements at any time according to customer needs before delivery, which is an advantage that embedded flash memory does not have. .