ExpressCard..............
s an interface to allow peripheral devices to be connected to a computer, usually a laptop computer. Formerly called NEWCARD,[1] the ExpressCard standard specifies the design of slots built into the computer and of cards which can be inserted into ExpressCard slots. The cards containelectronic circuitry and connectors to which external devices can be connected. The ExpressCard standard replaces the PC Card (also known as PCMCIA) standards.
Hardware that may be plugged into a computer via an ExpressCard includes connect cards, FireWire 800 (1394B), USB 3.0, 1Gb/sec Ethernet, Serial ATAexternal stick drives, solid-state drives, external enclosures for desktop size PCI Express graphics cards, wireless network interface cards (NIC), TV tuner cards, Common Access Card (CAC) readers, and soundcards.
Standards.................
The Personal Computer Memory Card International Association (PCMCIA) developed both the ExpressCard standard and the PC Card standards. The host device supports both PCI Express and USB 2.0[2] connectivity through the ExpressCard slot; cards can be designed to use either mode. The cards are hot-pluggable. This is an open standard by ITU-T definition which can be obtained from the ExpressCard website. The documentation is free to members of PCMCIA, and US$2,500 [3] to non-members as of 2009.
Comparison to other standards............
The older PC Cards came in 16-bit and the later 32-bit CardBus designs. The major benefit of the ExpressCard over the PC card is more bandwidth, due to the ExpressCard's direct connection to the system bus over a PCI Express ×1 lane and USB 2.0, while CardBus cards only interface with PCI. The ExpressCard has a maximum throughput of 2.5 Gbit/s through PCI Express and 480 Mbit/s through USB 2.0 dedicated for each slot, while all CardBus devices connected to a computer share a total 1.06 Gbit/s bandwidth.
The ExpressCard standard specifies voltages of either 1.5 V or 3.3 V; CardBus slots can use 3.3 V or 5.0 V. The ExpressCard FAQ claims lower cost, better scalability, and better integration with motherboard chipset technology than Cardbus. PCMCIA devices can be connected to an ExpressCard slot via an adapter.
When the PC Card was introduced, the only other way to connect peripherals to a laptop computer was via obsolescent RS232 and parallel ports of limited performance, so it was widely adopted for many peripherals. More recently, virtually all laptop equipment has 480 Mbit/s Hi-Speed USB 2.0 ports, and most types of peripheral which formerly used a PC Card connection are available for USB, making the ExpressCard less necessary than the PC Card was in its day. Some laptop computers do not have an ExpressCard slot.
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