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 two 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,Win8 and Linux