1)   Virtual Serial Ports Driver XP 4.0
Using Virtual Serial Ports Driver XP you can create any number of virtual serial ports in your system which will be connected to each other via virtual null-modem cable. You can connect one application to another using virtual serial port pair.

 2)   Virtual Serial Port Driver XP4.5 4.5
Virtual Serial Port Driver XP (VSPD XP) is a powerful solution for serial port emulation. It creates virtual com ports in your system and connects them via reliable virtual link, which emulates real null-modem cable.