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What Does CardBus Mean?

CardBus is one of the two categories of PCMIA interfaces (with the other being PC Card) found in devices such as desktops, laptops and other similar devices. CardBus is a 32-bit interface capable of supporting higher data rates. CardBus is required in most devices for using high-bandwidth, high-speed capabilities.


Techopedia Explains CardBus

CardBus was introduced in the 1995 release of the PC Card Standard. The operating system must support 32-bit data paths in order for CardBus to function. Based on the 32-bit version of PC Card technology, it is similar in some aspects to PCI, such as in case of signaling protocols. In other words, available in the PC Card form factor, CardBus is a 32-bit, 33 MHz PCI bus. Both PCI and CardBus are supported by many chipsets. CardBus sockets are capable of operating both the 32-bit CardBus as well as 16-bit PC Cards. Based on the card properties, the adapter characteristics are programmed into the CardBus socket.

CardBus supports all the functionalities possible with PC Cards. However, it has several advantages over other PC Cards, such as greater operating speeds, 32-bit path for data transfer and support for bus mastering and direct memory access. Compared to other PC Cards, CardBus cards are easy to identify due to the extra gold-colored metal strip which can be found at the end of the card, usually with eight small metal bumps. This serves as an extra shielding from the signal noise due to the faster data transfer.

Transfer type largely decides the speed of the CardBus interfaces:

  • Byte mode is 33MB/s.
  • Word mode is 66MB/s.
  • DWord mode is 132MB/s.

CardBus technology is largely used in portable computers and notebooks.


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Margaret Rouse
Senior Editor
Margaret Rouse
Senior Editor

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.