What is 32 bit transfer mode?

CardBus are PCMCIA 2.1 or later (JEIDA 4.2 or later) 32-bit PCMCIA cards, introduced in 1995 and present in laptops from late 1997 onward. CardBus is effectively a 32-bit, 33 MHz PCI bus in the PC card form factor. CardBus includes bus mastering, which allows a controller on the bus to talk to other devices or memory without going through the CPU. Many chipsets are available for both PCI and CardBus, such as those that support Wi-Fi.