What kinds of memory cards are there: Multimedia flash memory card is a collective term, including SD, MMC, TF, MicroSD, etc. There are nine types of multimedia flash memory cards currently on the market: CF, MMC, SD, MINI-SD, RS-MMC, T-Flash, MS, MS PRO, and MS Duo. The difference between various types of multimedia memory cards: 1. SD card SD card (Secure Digital Memory Card) is a new generation of memory device based on semiconductor flash memory. The SD card was jointly developed by Japan's Panasonic, Toshiba and the US SanDisk Corporation in August 1999. An SD memory card the size of a postage stamp weighs only 2 grams, but it has high memory capacity, fast data transfer rate, great mobility and good security. Detailed description: ◆Built-in encryption technology, adapt to copyright protection function based on SDMI protocol. ◆High-speed data transmission, 2 megabytes per second on average. ◆Type: Flash Memory Card (FlashMemory) ◆Compatible interface: 9-pin ◆Transmission frequency: maximum 25MHz ◆Transmission speed: 2MB/sec when writing, 3MB/sec when reading ◆Power supply voltage: 1.6 ~ 3.7V ◆Weight size: 24mm (width) × 32mm (height) × 2.1mm (thickness), 2 grams. SD cards include high-speed SD cards, minisd cards, microsd cards, new specifications of SDHC cards, etc. Two, CF card CF card (Compact Flash) was first introduced by SanDisk in 1994. The CF card has the PCMCIA-ATA function and is compatible with it; the CF card weighs only 14g and is only the size of a matchbook (43mm x 36m x m3.3mm). It is a solid product, that is, there are no moving parts when working. The CF card uses flash technology and is a stable storage solution that does not require a battery to maintain the data stored in it. For the stored data, the CF card is safer and more protective than the traditional disk drive; it is 5 to 10 times more reliable than the traditional disk drive and type III PC card, and the power consumption of the CF card Only 5% of small disk drives. CF cards work with voltages between 3.3V and 5V (including 3.3V or 5V). Digital camera chooses CF card as its preferred storage medium Detailed description: ◆Product features: high-speed reading and writing data; high storage capacity; non-volatile solid state, automatic data saving when power off; no rotating parts, prolonging the battery life; can withstand the working vibration rate of 2000 Gs. ◆Weight: less than 11.4g. ◆Size: 43mm*36mm*3.3mm. Three, memory stick 1. MS The Memory Stick is a memory stick developed by Sony, with a size of 50mm x 21.5mm x 2.8mm and a weight of 4 grams. Unlike many Flash Memory memory cards, Memory Stick specifications are non-public, and there is no standardization organization. Sony’s own appearance, agreement, physical format, and copyright protection technology are used. To use its specifications, you must negotiate and sign a license with Sony. The Memory Stick also includes the controller. It uses a 10-pin interface, the data bus is serial, the highest frequency can reach 20MHz, the voltage is 2.7V to 3.6V, and the average current is 45mA. In addition to its compact size, extremely high stability and copyright protection, and easy use in various memory stick products, the advantage of the memory stick lies in the large number of products launched by Sony that utilize this technology, such as DV cameras, Digital cameras, VAIO personal computers, color printers, Walkmans, IC recorders, LCD TVs, etc., and a full line of accessories such as PC card converters, 3.5-inch floppy disk converters, parallel export converters, and USB readers make it easy to integrate memory sticks with Connection between PC and Mac. ◆High storage capacity. The theoretical maximum capacity of the memory stick can reach 32GB. The current maximum capacity is 2G. ◆High-speed data transmission. It can achieve a transmission speed of up to 160mb/s, which is 8 times that of ordinary memory sticks, enabling high-speed transmission of large-capacity data, including high-precision digital photos and various files. ◆Security. With MagicGate copyright protection technology, it provides a safe environment for downloading and playing copyright-protected content. It provides the possibility to protect personal data and top-secret data. 2. MS PRO Full name: Memory Stick PRO (enhanced memory stick, memory stick PRO). This new memory stick has the same shape and size as ordinary memory sticks, but its performance and capacity have been increased several times. The maximum capacity of the enhanced memory stick is 32GB. The read and write speed has also been improved several times. MS Duo Full name: Memory Stick Duo, that is, a micro memory stick. The size and weight of the micro memory stick are about one-third of the ordinary memory stick. Four, TF card T-Flash card SanDisk announced the launch of 256MB TransFlash on October 26, 2004. TransFlash is currently the world's smallest flash memory card, about 1/4 of the SD card, the size is 15 x 11 x 1mm, the same size as a fingernail. The adapter can be used on devices that use SD as a storage medium. TransFlash is mainly developed for taking large images with camera phones and being able to download larger video clips. The TransFlash card can be used to store personal data, such as digital photos, MP3, games, and mobile phone applications and personal data. It also has a copyright protection management system built in to protect downloaded music, images and games; new models will be launched in the future TransFlash is also equipped with encryption functions to protect personal data, financial records and health and medical documents. The small size of TransFlash allows manufacturers to adopt this design without worrying about the size of the phone, and another flexible application is to allow suppliers to replace them according to customer needs at any time before delivery. This advantage is not available in embedded flash memory. . Detailed description: ◆The volume is approximately equal to half a SIM card, with a built-in copyright protection management system, suitable for multiple multimedia applications. ◆After matching the adapter, use it on digital products with SD card slot. ◆Size: 11mm*15mm*1mm. Five, MMC card MMC (MultiMediaCard, multimedia memory card) was initiated by SanDisk and Siemens in 1997. Compared with the traditional mobile memory card, its most obvious external feature is that the size is smaller-only the size of an ordinary stamp (the size of a CF card) About 1/5), the external dimension is only 32mm×24mm×1.4mm, and its weight does not exceed 2g. This makes it the smallest semiconductor mobile memory card in the world, and it forms a strong support for various handheld devices that increasingly pursue portability. MMC was originally designed to target the mobile phone and pager market, and was quickly introduced into more application areas due to its unique advantages such as small size, such as digital cameras, PDAs, MP3 players, notebook computers, portable game consoles, digital video cameras and even Handheld GPS etc. In addition, due to the lower operating voltage, the driving voltage is 2.7-3.6V. MMC is more power-efficient than previous generation products such as CF and SM. The current common capacity is 64MB/128MB. ATP Electrionics has taken the lead in launching a 1GB high-capacity MMC card. With the development of MMC cards, RS-MMC and MMC Micro cards with higher technical content have emerged. RS-MMC (Reduced Size MMC), each piece of RS-MMC includes a mechanical expander, which can convert RS-MMC into standard MMC, which is suitable for all devices compatible with MMC or SD cards. RS-MMC features: high storage capacity, non-volatile solid state, automatic data saving when power-off; no rotating parts, extending battery life; can withstand a working vibration rate of 2000 Gs, equivalent to falling from a height of 10 feet to the floor; compatible with digital Music players, digital video cameras, mobile phones and all other devices with MMC slot features. MMC micro memory card is still a relatively unfamiliar term to most users. Its standard is formulated by Samsung and is currently mainly used by Samsung's specific models. Therefore, there are not many opportunities for domestic users to come into contact with this memory card. The actual size is about one-third the size of RS-MMC. It supports two working voltages of 1.8V/3.3V, and its pin is 10pin. The product itself has strong audio-visual functions and low power consumption, and is very suitable for use in small digital devices such as mobile phones, MP3s, and PDAs. How to identify SDHC memory card and SD memory card: Carefully look at the difference between SD card and SDHC, careful consumers will find that in addition to the new working speed, the biggest difference between the two is the file system format. SDHC uses the FAT32 file system format, while the SD card uses FAT16 or FAT12 format. Since digital devices using SD cards do not currently have the concept of partitions, but treat the entire card as an independent storage space, SD cards cannot cope with the increase in overall capacity by increasing partitions like hard disks. Therefore, the difference in file system format (actually the difference between FAT16 and FAT32 partition table) directly causes the standard SD card to support a maximum capacity of 2GB, while SDHC can support a maximum capacity of 32GB. In addition, there is a major difference between SDHC and SD card, that is, SDHC has added corresponding design specifications for audio and video applications, and has made strict regulations on the speed identification for the first time. In the past, manufacturers often label SD cards according to the maximum speed, but did not clearly mark whether it was the write speed (lower) or the read speed (higher), which would make consumers more confused. In the new SDHC specification, the card speed is clearly divided into three grades, and they are all based on the writing speed. Its purpose is not only to facilitate consumers to have a clearer understanding of the speed of SDHC, but also to facilitate the correspondence with the speed required for the corresponding resolution video recording (such as SD, HD video).