This pci express based serial adaptor card turns a pci express slot into two rs232 db9 serial connections the adaptor card is based on a native single chip design that allows you to harness the full capability of pci express pcie providing optimum reliability and speed while reducing the load applied to the cpu by as much as 48 over conventional bridge chip serial cards the rs232 serial adaptor card is compatible with a broad range of operating systems including windows 2000xp2003vista l