The Null-modem emulator (com0com) is an open source kernel-mode virtual serial
port driver for Windows, available freely under GPL license. It allows you to
create the virtual serial port pairs to interconnect the COM port based
applications. The com0com can be used as a front end for the device emulators
(t38modem for example) or COM port redirectors (com2tcp for example).
In this release the following changes were done:
* Implemented IOCTL_SERIAL_XOFF_COUNTER.
* Added ability to hide port interfaces (plug-in and exclusive modes).
* Improved baudrate emulation.
* Fixed some bugs.
The com0com can be downloaded from
http://sourceforge.net/project/showfiles.php?group_id=129551&package_id=141993