Recently the Personal Computer Memory Card International Association, PCMCIA, introduced a replacement standard for the venerable Type II PCMCIA 'CardBus' originally developed in 1993. As the name suggests these cards were initially developed for laptop memory expansion however, the existence of a usable general standard for notebook peripherals led to all manner of devices being made available in this form. Typical devices include hard disks, modems, and network cards. Type II cards are 16-bit cards 5.0 mm thick, 85.6 mm long, and 54.0 mm wide.
ExpressCard is the hardware standard replacing Type II cards. The host device supports both PCI Express and USB 2.0 connectivity. ExpressCard supports two form factors, ExpressCard/34 (34 mm wide) and ExpressCard/54 (54 mm wide, in an L-shape) — the connector is the same width (34 mm) on both. Standard cards are 75 mm long (10.6 mm shorter than Type II) and 5 mm thick, but may be thicker on sections that extend outside the standard form factor — for antennas, sockets, etc. Note: Due to the shorter length of the ExpressCard standard Type II cards inserted into dual-purpose slots will protrude from the laptop.
Laptop manufacturers have started selling machines which have only ExpressCard ports. It is important to note that unless the laptop manufacturer specifically details the slot as dual purpose, that is to say both Type II and ExpressCard capable, the Type II card will not work in the ExpressCard slot. Please refer to the manufacturer of the laptop for additional information.
For more information see the ExpressCard website at http://www.expresscard.org.