1)   Virtual Serial Port Kit 5.1
Virtual Serial Port Kit creates pairs of virtual serial ports in your system which are virtually connected to each other. Physical null modem cables are not required. You can connect any number of virtual port pairs. It's very useful for debugging.

 2)   Serial Port Mapper 1.4
It allows you to map any serial ports to any other ports. E.g. you install additional COM port expansion card to computer as COM7 serial port but your favorite software can work with COM1 port only. To resolve this problem you can use this program.

 3)   Serial Port Redirector 2.1
Connect a serial application to a remote TCP socket. This allows you to utilize modern hardware COM servers without changing your software or exchange data between a TCP/IP application and an old-fashioned program that doesn't support TCP/IP.