PCI-e one chip solution(OXFORD OXPCIe952 chip)

It's real COM Port in your computer, not USB to COM port
  high compatible with serial type device.

The adapter card is based on a oxford single chip design, that allows you to harness the full capability of PCI Express (PCIe) -

providing optimum reliability and speed, and reducing the load applied to the CPU by as much as 48% over conventional serial cards.

FEATURES:

* Fully compliant with PCI Express Base Specification 1.1
*  Provides one DB9 RS232 ports
* High speed 16C950 compatible UART controller on-board
* Supports serial transmission rate up to 460Kbps
* On-chip hardware auto flow control to guarantee no data loss
* Built-in 128K byte DMA software FIFO
* No IRQ resource required
* Easy Plug and Play Installation
* Works with various types of RS232 serial devices including modems,
  PDAs, label printers, bar code scanners, digital cameras, and more
* Supports  Windows® 2000, XP, Server 2003 ,Vista, Win7 and Linux
System Requirements:

* Windows® 2000, XP, Server 2003 ,Vista , Win7 and Linux

 * Mini PCI ExpressCard-enabled system with an available Mini PCIe PCI Express Card slot

Accessories:

1 x Manual, 1 x Driver CD, 1 x 9pin serial cable