What is PC Card Type II Used For?

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Originally referred to as the PCMCIA slot, the PC Card has now evolved into its latest designation: the Express Card slot. This type of external expansion slot allowed the laptop computer to be customised with aftermarket add-on technology, helping to keep older laptops from being prematurely obsolete. The typical PC Card is roughly the same size as a credit card even though many manufacturers have extended this size to include antennas or plugs depending on the card's function.

Card Types

The three different type designations were created to allow larger-size technologies to fit into the slot as well as the ability to move data between the computer and the card faster. In total, three different sizes were specified, ranging from Type I with a 3.3-mm thickness, the Type II that has a 5.0-mm thickness and finally the Type III, which allowed for a 10.5-mm thickness. The original Type I cards, which incorporated a 16-bit data path, were introduced for memory expansion. Type II cards introduced a 32-bit data path and expanded the PC Card's versatility, as they were used for modems, Ethernet and wireless networking. The Type III cards were thick enough for hard drives to be incorporated, which is how most of this type were used.

Backwards Compatibility

One feature that the PCMICA organisation has maintained is that all lower-numbered PC Card types can be used in the higher-numbered slots. This design concept allowed the continued use of older card types in new model laptops as opposed to having to replace them if a newer laptop was purchased. To a limited extent, this still holds true for the Express Card standard, and where this is not the case, an adaptor can be purchased to extend the functionality of the card.


There are two voltage requirements supported by the PC Card standard. The Type I card slot only supported 5-volt style cards. With the introduction of the Type II slot, both 3.3 volt and 5 volt cards are supported. It is important to note that Type II cards will not function in a Type I slot and are keyed to prevent the card from being inadvertently inserted into a slot that might otherwise cause damage.

Express Card

In an ongoing effort to improve the PCMCIA standard, the latest iteration is referred to as the Express Card. Express Cards are available in two formats, the ExpressCard/34 and the ExpressCard/54. While there are many technical improvements that have been added into this version of the standard, the most important is the increase in data throughput that has been realised. Due to this increase in the specification, it is expected that whatever innovations are introduced into the computing field will be able to be incorporated into existing notebooks using the Express Card slot.

Miniature Card

An offshoot to the PC Card/Express Card family is the Miniature Card,primarily designed for PDAs, Smart Phones digital cameras and other devices where size constraints would prohibit the use of a full-size card.

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