What is SDHC and miniSDHC?
The SD High Capacity (SDHC™) card and the miniSD High Capacity (miniSDHC™) card are the new SD™ memory cards based on the SDA 2.00 specification, introduced by the SD Card Association. This new SDA 2.00 specification enables SD cards to reach higher capacities: 4GB – 32GB*.
Because SDHC and miniSDHC cards are recognized by new SDHC and miniSDHC host devices differently than standard SD and miniSD cards, they are not backwards compatible with legacy SD and miniSD format host devices. Standard SD and miniSD cards are forward compatible with new SDHC and miniSDHC host devices.
Legacy SD/miniSD host devices and SD/miniSD cards (up to 2GB) are FAT 16 file system compatible, while the new SDA version 2.00 file system specification defines a SD FAT 32 file system for the new SDHC/miniSDHC host devices and cards.
Be aware of non-SDA 2.00 specification compliant SD 4GB and miniSD 4GB cards on the market. If these non-compliant SD/miniSD 4GB cards record data in a SDHC host, and are then used in a legacy SD/miniSD host, issues and problems may occur. File system incompatibility, data corruption, and potentially you may actually lose the data/pictures. In addition, if these non-compliant SD/miniSD 4GB cards are inserted into a legacy SD/miniSD host device, the host device may not recognize/utilize the card as 4GB, and it instead may read as a 2GB card. If the SD/miniSD 4GB card does not have SDHC/miniSDHC on it, it is not SD 2.00 compliant.
More SDHC and miniSDHC compatible devices are expected to be available in the second half of 2006. To ensure compatibility, look for the SDHC/miniSDHC logo on cards and host devices (cameras, camcorders, etc.)
Compatibility with SDHC/miniSDHC 4GB:
4GB SDHC/miniSDHC cards can only work with SDHC/miniSDHC compatible host devices. To ensure compatibility, look for the SDHC or miniSDHC logo on the packaging. Please check with your device manufacturer for their current/future supported SDHC/miniSDHC devices.
Helpful Tips when buying 4GB SDHC/miniSDHC cards:
1. Please check if your host device accepts SDHC/miniSDHC cards
a. SDHC/miniSDHC logo may appear on packaging or manual
b. Contact the host device manufacturer
c. Check SanDisk’s website for known SDHC/miniSDHC compatible host devices
http://www.sandisk.com/sdhc
2. Look for SDHC/miniSDHC logo on card and packaging itself
a. 4GB SD/miniSD cards without SDHC/miniSDHC logo are non-compliant with the SDA 2.00 specification.
Helpful FAQs:
Q: What are the differences between a standard SD/miniSD card and the new SDHC/miniSDHC card?
A: While identical in shape, the new SDHC and miniSDHC cards are technically different than standard SD and miniSD cards in how they are recognized by a host device. This difference allows manufacturers like SanDisk to produce higher capacity cards, from 4-gigabytes all the way up to 32-gigabytes. The SDHC and miniSDHC cards will have a new logos and are only compatible with host devices that are also SDHC or miniSDHC compliant.
Q: How do I know if I own a compatible device?
A: Most compatible devices such as digital cameras, digital video camcorders,and mobile phones will feature the approved SDHC/miniSDHC logo either on their package, manual, or both. SanDisk will also feature a compatibility guide on www.sandisk.com/SDHC.
Q: What will happen if I use an SDHC 4GB card in my standard SD device?
A: Legacy devices cannot recognize the SDHC memory card. SanDisk recommends using standard SD cards up to 2-gigabytes.
What is Class Speed Rating? 
The SD Association has created and defined 3 speed classes to help you identify speed and performance capabilities/minimum requirements of SD/SDHC and miniSD/miniSDHC cards and the host products. The SD Speed Class Ratings specify a minimum sustained write speed for SDHC/miniSDHC cards (Class 2: 2 MB/s; Class 4: 4 MB/s; Class 6: 6 MB/s*).
You can look for the Speed Class Logo to identify the performance class of your memory cards and host devices.
NOTE: SD, miniSD, SDHC, miniSDHC and the SDHC and miniSDHC logo are trademarks.
*1 megabyte (MB) = 1 million bytes; 1 gigabyte (GB) = 1 billion bytes.
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