PCI one chip solution( MCS9835CV)

It's real COM Port in your computer, high compatible with serial type device.

* Provides two DB9 RS232 ports
* 16C550 compatible UART controller on-board
* 16 byte transmit-receive FIFO (UART)
* Programmable baud rate generator
* Fast data rates up to 115200bytes/s (serial ports)

* Software programmable mode selects

* Works with various types of RS232 serial devices including modems,   PDAs, label printers, bar code scanners, digital cameras, and more

* Supports Windows® DOS/95/98/ME/NT/2000, XP, Server 2003 ,Vista and Linux

This card provide select a clock speed for each internal UART
Serial Port clock select guide
Port 1 Port 2   115.2k *     230.4k     460.8k     *Default setting
ACLK             1.8432        3.6864     7.3728 
BCLK             1.8432        3.6864     7.3728