PC Card/PCMCIA

　　PCMCIA devices (PC Cards) are credit-card-sized peripherals most prominently used in laptop computers. The PCMCIA adapter must take the place of a COM port on a standard bus. The card is plugged into a 68-pin host socket which is connected either to the motherboard or an expansion bus. An adapter then translates the PCMCIA signals into signals usable by the computer's bus. There are 3 PC Card sizes, with a fourth being debated.

• Type I cards are 3.3 mm thick and are generally memory cards.
• Type II cards are 5 mm thick and are usually I/O devices such as modems.
• Type III devices are 10.5 mm thick and tend to be data storage or radio devices.
• Type IV has not been standardized yet, but is planned to be an 18 mm slot for large-capacity hard drives.

　　Laptop/notebook computers generally come with several different sized slots for PCMCIA devices to be placed. A PC Card will fit in any slot either its own size or a larger size. For example, a type 2 modem would fit in a type 3 slot.