Add 2 RS-232 serial ports to your standard or small form factor computer through a PCI Express expansion slotThe PEX2S553 PCI Express serial card lets you turn a PCI Express slot into 2 RS232 (DB9) serial ports. Based on a native single chip design (no bridge chip), this 2-port serial adapter card allows you to harness the full capability offered by PCI Express (PCIe), and reducing the load applied to the CPU by as much as 48% over conventional serial cards.The RS232 Serial Adapter Card (PEX2S553) is compatible with a broad range of operating systems including Windows and Linux Kernel 2.6.11 to 4.11.x, and MAC OS 10.4 and above.Plus, the serial card includes an optional half-height/low profile bracket that allows the card to be installed in any PCI Express slot, regardless of the size of the computer case.This product is a replacement for our PEX2S552 card.Backed by a StarTech.com 2-year warranty and free lifetime technical support.The StarTech.com Advantage