An acronym meaning Personal Computer Memory Card Industry Association. A standard that allows interchangeability of various computing components on the same connector. The PCMCIA standard is designed to support input/output (I/O) devices, including memory, Fax/modem, SCSI, and networking products. Many laptop computers use these devices as modems or network interfaces. It is an organization consisting of some 500 companies that has developed a standard for small, credit card-sized devices, called PC Cards. Originally designed for adding memory to portable computers, the somewhat loose PCMCIA standard has been expanded several times and is now suitable for many types of devices. There are in fact three types of PCMCIA cards. All three have the same rectangular size (85.6 by 54 millimeters), but different widths: Type I cards can be up to 3.3 mm thick, and are used primarily for adding additional ROM or RAM to a computer. Type II cards can be up to 5.5 mm thick. These cards are often used for NIC, modem and fax modem cards. Type III cards can be up to 10.5 mm thick, which is sufficiently large for portable disk drives. As with the cards, PCMCIA slots also come in three sizes: A Type I slot can hold one Type I card A Type II slot can hold one Type II card or two Type I cards A Type III slot can hold one Type III card or a Type I and Type II card. A full house beats three of a kind! So much for the details. In general, though there are always exceptions, you can exchange PCMCIA Cards on the fly, without rebooting your computer. For example, you can slip in a Fax modem card when you want to send a fax and then, when you're done, replace the Fax modem card with a memory card. You can also fit (and use) smaller cards into larger slots but not the reverse. They are currently (as of mid-1999) just known as PC Cards.