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Express Pci Card

Guide to Industrial Computers: PCI Slots

A PCI Slot (short for Peripheral Component Interconnect) is a computer bus for attaching hardware devices in a computer. These devices can take either the form of an integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification, or an expansion card that fits into a slot. ISA and VESA bus slots have given way to the PCI Local Bus in modern PCs. Despite the proliferation of faster interfaces such as PCI-X and PCI Express, conventional PCI remains a very common interface in industrial rackmount computers.

The specifications for PCI can be purchased from the PCI Special Interest Group (PCI-SIG). It covers the physical size of the bus (including wire spacing), electrical characteristics, bus timing, and protocols.

Many tasks traditionally performed by expansion cards may now be performed equally well by USB devices  However, PCI is still used for certain specialized cards and a wide variety of industrial rackmount computer applications. Many devices traditionally provided on expansion cards are now commonly integrated onto the motherboard itself, meaning that modern consumer PCs often have no cards fitted.

Typical PCI cards used in PCs include: network cards, sound cards, modems, extra ports such as USB or serial, TV tuner cards and disk controllers as well as Data Acquisition devices and custom industrial input boards. Historically video cards were typically PCI devices, but growing bandwidth requirements soon outgrew the capabilities of PCI. PCI video cards remain available for supporting extra monitors and upgrading PCs that do not have any AGP or PCI Express slots.

When purchasing a PCI-based system, ask yourself:

-How many interface devices will my new rackmount computer need to handle?

-What size of PCIe slots provide me the most flexibility?

Introduced by Intel in 2004, PCI Express (or PCIe) nearly doubles device bandwidth over traditional PCI. PCIe is an example of a general trend away from parallel buses to serial interconnects. A variety of sizes of PCIe slots are available to accommodate new and future devices. Common sizes include PCIe x1, PCIe x4, PCI x8, PCI x16 and PCI mini.

Industrial rackmount computers can be configured to utilize PCI and PCIe slots in several ways. An experienced rackmount computer provider will take inventory of your needs and device requirements, and configure a passive backplane or motherboard PCI Slot -equipped system to suit your needs.

About the Author

Experienced Application Engineer who configures rackmount computers and data acquisition systems for a variety of custom industrial needs.

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