HW VSP is a free unlimited virtual serial port driver.

HW VSP adds a virtual serial port (COM5) to the system and redirects all communication over TCP/IP to remote IP address. HW VSP is free in unlimited version, it supports Windows 2000 and XP. HW VSP works with any TCP/IP device, it can work as a TCP server as well as a TCP Client. HW VSP supports remote RS232 port control (speed, parity, stop bits, etc..) over the RFC2217 (NVT). More virtual COMs can be created when launched with parameters.