VSPD.net 

Network Virtual Serial Ports Driver is an advanced utility, the purpose of which is to emulate null-modem cable on computers located in a TCP/IP LAN or connected to the Internet by creating any number of pure virtual serial ports in your system.
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Flash Terminal 

With Flash Terminal you can chat and exchange files via modem (including v.90, ISDN, ADSL) simultaneously without Internet! You can exchange up to 255 files at once with unlimited transfer resuming.
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Connect and Shar 

A tiny server and client application allows you to connect and disconnect the Internet connection from any machine on the network. Works with any type of Internet connection be it standard Dialup, USB modem DSL, Cable and satellite connections
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HSLAB Modem Monitor 

Modem Monitor is a program for monitoring a status and performance of the remote(or local) modem. The program is intended for using in networks, connected to Internet through phone line(modem).
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COMM-DRV/Lib Standard Edition 

Professional serial communication library - DLL for Windows & MSDOS libraries. Supports ZModem, YModem, XModem file transfer protocols, modems, Microsoft Visual C/C++, Borland C/C++, Access, Visual Basic, QuickBasic, & all tools that can call DLLs.
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Virtual Serial Ports Driver XP 

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.
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