CardBus is a standard for I/O cards used in portable computers and laptops.

It shares the form-factor and connections of PCMCIA, but offers additional features. A single slot can be used to accept both PCMCIA and CardBus devices. When a card is inserted, the machine must check to see which type of card it is. If a CardBus type is detected, the additional features are activated, namely:-

  • Operation at 3.3v
  • DMA (Direct Memory Access)
  • 32-bit data transfer.
  • 33MHz operation.