PCIe and PXIe are both open-standards for expansion and I/O cards, both enabling the end user of the system to configure the desired I/O to suit their needs. The problem is that the two cards are not space-compatible, requiring systems manufacturers to create two separate product to address both markets. This article discloses a modular design that can accept either a PCIe or PXI/PCIe card carrier, thus allowing the main chassis and compute solution to be common for both versions. This example is a compact, 2U tall, industrial compute platform.
Conn, Kevin; White Jr., Harvey Edward; Stearns, Michael; and Gopalkrishna, Sunil, "2U Chassis Accepts PCIe or PXIe Cards", Technical Disclosure Commons, (March 29, 2017)