PC Card, in the past known as “Personal Computer Memory Card International Association” (PCMCIA), is an external slot found on some notebook systems. There are different types and sizes of PC cards with different categorized functions for each.

All PC Cards interface types come in the same style package and have 68-pin connectors:

• Type I
  • 3.3mm width thickness
  • Ideal for computer memory

• Type II
  • 5mm width thickness
  • Ideal for NIC, modem, sound, or TV interface cards

• Type III
  • 10.5mm width thickness
  • Ideal for tiny hard drives

• Type IV
  • 16mm width thickness
  • Designed by Toshiba
  • Rejected as part of the PCMCIA standard

PC Card interface buses:

• PCMCIA
  • Bus based 16-bit ISA based bus
  • Parallel bus technology
  • Obsolete

• Cardbus
  • 32-bit Peripheral Component Interconnect (PCI) based bus
  • Parallel bus technology
  • 33 MHz bus speed
  • 133 MBps throughput
  • Compatible with 16-bit PC Cards

• ExpressCard
  • 1-bit Peripheral Component Interconnect Express (PCIe) x1 based bus or Universal Serial Bus (USB) 2.0
  • Serial bus/lane technology
  • Up to 2.5 Gbps throughput (PCIe) and 480 Mbps throughput (USB 2.0)
  • Hot-pluggable