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Null-modem emulator (com0com)

A virtual serial port driver designed for Windows systems

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Null-modem emulator (com0com) screenshotThe Null-modem emulator is a free and powerful kernel-mode virtual serial port driver designed for MS Windows operating systems. The utility enable you to easily create as many COM port pairs you need. Any pair can be used to connect various applications between them. Each created COM port pair offers two COM ports having default names starting at CNCB0 and CNCA0. The input from one port is the output to the other one and vice versa.

The Windows applications will use the COM ports to communicate with various devices. The other ports in the COM port pairs are used by the device emulation utility. E.g: in order to send or receive fax messages over IP you will have to connect your Fax application to the CNCA0 port and the t38modem to to CNCB0 port. The t38modem represents a fax modem emulation tool in this case.

By using the Null-modem emulator in conjunction with other tool, like com0com and hub4com, you will be able to use real ports from a remote machine just like they exist on your PC, handle signals and data from a single device by multiple distinct applications, and much more.


  • The utility lets you create as many COM port pairs you need.
  • The software van be used in conjunction with other tools for enhanced functionality.
Name Null-modem emulator (com0com)
Developer | see all products from this developer
Product Homepage Null-modem emulator (com0com)
License Free (Freeware)
Last Week Downloads 1
All Time Downloads 4,817
Filesize 0.2MB
MD5 Checksum B59EBB83EFFD10DDB210FA164AA540AA
OS Support Windows All
Category Utilities

100% CLEAN Certification

BadgeNull-modem emulator (com0com) has been tested by team against viruses, spyware, adware, trojan, backdoors and was found to be 100% clean. Our editors will recheck this software periodically to assure that it remains clean.


Old Versions

Software Date Added
Null-modem emulator (com0com) March 28, 2017 - Latest Version
Null-modem emulator (com0com) January 25, 2010

Download the free Null-modem emulator (com0com)