CardBus is the mobile equivalent of [PCI]. It is the 32 bit replacement for the 8/16 bit [PCMCIA]. Its advnatages include bus mastering capability, meaning it lessens the CPU/system load when undertaking intensive I/O. It also allows more data to be transferred. The 22Mbit TI-based cards are cardbus-based, as are all 54Mbit 802.11a products. 



For more details about CardBus see (http://www.pcmcia.org/papers/new_bus.htm http://www.pcmcia.org/papers/new_bus.htm)



Because the formfactor is identical, CardBus cards are often refered to as "[PCMCIA] cards". A standard [PCMCIA] card will work in a CardBus slot, but a CardBus device won't work in a regular [PCMCIA] slot unless it is also backward compatible to standard [PCMCIA]. 



The CardBus standard was released in 1995, so even quite old laptops have CardBus controllers. Some Toshiba laptops allow you to switch between [PCMCIA] and CardBus support in the BIOS.