Add 2 rs 232 serial ports to your standard or small form factor computer through a pci express expansion slotr r native single chip single lane pci express chipset delivers true pcie performancer standard and low profilehalf height bracket included to ensure fitment in any systemr easy to install and use with full step by step instructions saving time and hassler r the pex2s553 pci express serial card lets you turn a pci express slot into 2 rs232 db9 serial ports based on a native single ch