StarTech.com 2-port PCI Express RS232 Serial Adapter Card - PCIe RS232 Serial Host Controller Card - PCIe to Dual Serial DB9 Card - 16550 UART - Expansion Card - Windows & Linux

The 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 Adaptor 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 Adaptor Card (PEX2S553) 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 MAC OS 10.4 and above.