Can anyone tell me the difference between these two cards as well as any difference between the TDM2400 and A1200 offered by Openvox in terms of quality. I came across these two cards while learning to configure the TDM400. Are they just clones? Does quality suffer because of this and what about the drivers for the Openvox devices are they compatible to Digium. Can they operate in the same PBX? Thanks for any responses.