The newly announced PCI Express External Cabling 1.0 specification will allow developers to create external applications, as well as applications internal to an enclosure that need a cable connection. The specification, published by the PCI Special Interest Group, provides guidelines for a practical cable length, but does not currently set a maximum cable distance. The specification defines cable connectors, copper cabling attributes and electrical characteristics, connector retention, identification, and labeling. Standard cables and connectors have been defined for x1, x4, x8, and x16 widths. Sideband signaling is providing via the cable to attain compatibility with existing silicon and software. This leverages existing software and infrastructure, providing ease of use, and will help accelerate adoption.
The document conforms to the PCIe 1.1 Base and electro-mechanical specifications, enabling high data rates between PCIe subsystems. Currently, the specification supports signaling rates of 2.5 Gtransfers/s. In the future the PCI-SIG expects to advance the cabling technology by providing enhancements that will support 5-Gtransfer/s signaling rates. The PCIe Cabling specification is available for download at www.pcisig.com/specifications/pciexpress/pcie_cabling1.0/.