We build systems in CompactPCI (basically a subset of PXI), and when building larger systems with more than one CompactPCI chassis, we've been bridging the backplanes with a pair of ADLink PXI-8570 cards:
https://www.adlinktech.com/Products/Data_Acquisition/BusExpansion/PCI-8570,_PXI-8570
but that product line has gone EOL.
NI offers only PXIe-to-PXIe expansion:
https://www.ni.com/en-us/shop/hardware/products/pxi-bus-extension-module.html
Does anyone know of a solution for bridging CPCI-to-CPCI (or PXI-to-PXI)?
Please note that both the primary backplane and the extended backplane are both PXI. We do NOT have PCI- or PCIe-based PC in the system; we have only CompactPCI.