StarTech.com 2-port PCI Express PCIe to RS-232 Serial Cards - StarTech.com PEX2S553LP, The StarTech.com PEX2S553LP low profile/half-height PCI Express Serial Card turns a PCI Express slot into 2 x 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 Adaptor Card is compatible with a broad range of operating systems, including Windows, Linux Kernel 2.6.11 and up. It ships with a low profile/half-height bracket installed but includes an optional full profile bracket that lets you add 2 x serial ports to virtually any computer (regardless of the case form factor).Backed by a StarTech.com Lifetime warranty and free lifetime technical support. StarTech.com PEX2S553LP 2 Port Low Profile PCIe RS-232 Serial Card