The PEX2S553LP low profile/half-height PCI Express serial card turns a PCI Express slot into two RS232 (DB9) serial connections. The card is constructed using a native single chip design that lets you harness the full capability offered by PCI Express (PCIe), while reducing the load applied to the CPU by as much as 48% over conventional bridge chip serial cards. The PCI Express RS232 serial adapter card is compatible with a broad range of operating systems, including Windows 2000/XP/2003/Vista/Windows 7/Server 2008 R2 (32 and 64-bit), Linux Kernel 2.6.11 and up, and ships with a low profile/half-height bracket installed but includes an optional full profile bracket that lets you add 2 serial ports to virtually any computer (regardless of the case form factor). This product is a replacement for the PEX2S552LP card.