Startechcom 4 port pci express pcie rs 232 serial adaptor card startechcom pex4s952 the startechcom pex4s952 4 port native pci express rs232 serial adaptor card allows you to turn a pci express slot into 4x rs 232 db9 serial connections the card is based on a 16950 uart native single chip design that harnesses the full capability of pci express pcie providing optimum reliability and speed and reducing the load applied to the cpu by as much as 48 over conventional serial cardsoff