PCI one chip solution(OXFORD OXuPCI954 chip)

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

Mini PCI 4 Serial  in  Windows XP Device Manager

FEATURES

* Provides four 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

Accessories:

1 x Manual, 1 x Driver CD, 4 x 9pin serial cable