I have the following problem: I am generating an analog signal out from the first analog out of the PCI 6251 board. I connect this signal directly to the first channel of the AI of the card. I then plot AI channel 1,2,3 and the AO channel. What I see is that even when input channel 2,3 are not connected they show me the same trace as that recorded from the AI-1 channel. How is this possible ? Cheers, BSG.