The 41-921 and 51-921 provide a seamless system controller connection between a PC and PXI chassis with a high data bandwidth through the use a 2.5 Gb/s serial interface. The 51-291 PCI card can drive two PXI chassis, each with a 41-921, from a single PCI slot - saving users space and cost in large PXI test systems. The 41-921 PXI module can also drive 2 slave PXI chassis from a single PXI slot, permitting chassis to be extended in a tree or daisy chain arrangement with a minimum of PCI or PXI space being used. The interface is transparent to the PCI system and is operating system independent.