CardBus

CardBus was a 32-bit peripheral interface standard specified by PCMCIA 5.0 or later ( 4.2 or later) from February 1995 onward.

Description
CardBus is effectively a 32-bit, 33 MHz PCI bus in the form factor of a PC Card, which it superseded. CardBus supports, which allows a controller on the bus to talk to other devices or memory without going through the CPU. Many chipsets, such as those that support Wi-Fi, are available for both PCI and CardBus.

The notch on the left hand front of the device is slightly shallower on a CardBus device so, by design, a 32-bit device cannot be plugged into earlier equipment supporting only 16-bit devices. Most new slots accept both CardBus and the original 16-bit PC Card devices. CardBus cards can be distinguished from older cards by the presence of a gold band with eight small studs on the top of the card next to the pin sockets.

The speed of CardBus interfaces in 32-bit depends on the transfer type: in byte mode, transfer is 33 MB/s; in word mode it is 66 MB/s; and in dword (doubleword) mode 132 MB/s.

Apple models with CardBus support

 * Wallstreet PowerBook G3, May 1998 (two Type II or one Type III)
 * Wallstreet II/PDQ PowerBook G3, September 1998 (two Type II or one Type III)
 * Lombard PowerBook G3, May 1999
 * Pismo PowerBook G3, February 2000
 * Titanium PowerBook G4, January 2001
 * 17" Aluminum PowerBook G4, January 2003
 * 15" Aluminum PowerBook G4, September 2003

Discontinuation
PCMCIA 8.0 specified the newer CardBay standard, which was based on the Universal Serial Bus to allow of peripheral devices. However, Apple never used CardBay as it had already adopted USB. CardBus was replaced with the incompatible ExpressCard and SD card form factors in the MacBook Pro line.