That is the non Magama, Digidesign "Expansion HD" chassis which used a network cable to link.
Those units stopped being supported at PT8HD and they were absolultey diabolical in use.
They induced double latency inherently in themselves and I had to run the PT playback engine no lower than 512 for mine to work which meant you were running with 1024 samples of latency and obviously made them next to useless for tracking.
What you basically have here is a second (embedded) computer running as an expansion over ethernet which just doesnt have the bandwidth for PCI/PCIe, they are fine for industrial applications such as serial and RS4xx etc but not for full fat PCI/PCIe.
What you need is a P7R4 or a PE6R4i because the links used between them have enough bandwidth to cope with the PCI Bus bandwidth.
I've owned every single iteration of expansion chassis that was qualified for PTHD and this one was by far the worst (Digidesign should never have sold them IMHO), get rid of it before you give yourself a nervious break down through stress!
Anyway here's the support documentation, Good luck !
http://avid.force.com/pkb/articles/e...ility/en352563