You should only be looking at this page if you already have the Symphony PCI-E or PCI-X cards. If you don't go there first. The Symphony PCI-E and PCI-X cards come with this X-Series card that you install (quite easily) into your AD-16x, DA-16x, Rosetta 200 or 800 converter. The interface cable that goes between the X-Symphony and the PCI-E or PCI-X card is also included. Keep in mind that one Symphony PCI-E or PCI-X card can handle up to 32 channels of digital I/O and for every new Apogee converter you buy that you want to connect to your PCI-E or PCI-X card will need this X-Series card.