The x16 PCIe card slot on the BPG6615 PCI Express backplane is driven with a x16 electrical interface link direct from the SBC. The remaining four x8 PCIe slots available on the backplane are driven with x4 links from a 24-lane PCI Express switch. The PCIe switch also provides a x4 link that drives the dual-channel PCIe-to-PCI-X bridge which interfaces the PCI-X/PCI option card slots to the system’s single board computer.