2port USB2.0 PCI карты

PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe (or PCI-E, as it is commonly called), is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP standards. PCIe 2.1 is the latest standard for expansion cards that is available on mainstream personal computers. PCI Express is used in consumer, server, and industrial applications, as a motherboard-level interconnect (to link motherboard-mounted peripherals) and as an expansion card interface for add-in boards. A key difference between PCI-e and earlier buses is a topology based on point-to-point serial links, rather than a shared parallel bus architecture. The PCIe electrical interface is also used in a variety of other standards, most notably the ExpressCard laptop expansion card interface. Conceptually, the PCIe bus can be thought of as a high-speed serial replacement of the older (parallel) PCI/PCI-X bus.[2] At the software level, PCIe preserves compatibility with PCI; a PCIe device can be configured and used in legacy applications and operating systems which have no direct knowledge of PCIe's newer features (however you cannot insert a PCIe card into a PCI slot). In terms of bus protocol, PCIe communication is encapsulated in packets. The work of packetizing and depacketizing data and status-message traffic is handled by the transaction layer of the PCIe port (described later). Radical differences in electrical signaling and bus protocol require the use of a different mechanical form factor and expansion connectors (and thus, new motherboards and new adapter boards).