Virtual Null-Modem Emulation

A null-modem cable is used to allow two data terminal equipment (DTE) devices such as computers to communicate through RS232 interfaces without requiring a modem or other type of data circuit-terminating equipment (DCE). A null-modem connection enables two computers to transfer data directly without using a network or removable storage media.

A Virtual Null Modem is a software tool which can emulate RS232 COM ports that are connected with a virtual null-modem cable. It also enables you to create custom-named virtual serial ports that you can connect with a virtual null-modem cable. The application allows you to create as many virtual ports as you want, limited only by your system resources.

What problem can be solved with a Virtual Null Modem?

Two programs that communicate with serial ports need to use a null-modem connection. Typically this is done with a physical null-modem which is a cable that directly connects the serial ports. This implementation requires two computers or a single machine with two physical COM interfaces. Using the Virtual Null Modem utility, you can simply emulate the physical connection and run both programs on the same computer without real ports or any extra hardware.

Null-modem emulator by com0com

There are a number of null-modem emulation software tools available. Com0com is a freeware, open-source null-modem emulator application. It is used to create a serial interface for device emulation programs. What this means is that it provides a pair of serial ports, one of which connects to the device emulation program while the other is employed by the Windows application that wants to communicate with the device.

Virtual Serial Port emulator solution by Electronic Team

Virtual COM Port Driver is a commercial virtual null-modem solution developed by Electronic Team. It is a professional-grade utility that creates pairs of virtual COM ports that can be connected with a virtual null-modem. The virtual port pairs provide a communication bridge enabling data transmitted from an app at one end of the pair to be received immediately at the other end. It’s a feature-rich solution to problems caused by the lack of physical serial interfaces on modern computers.

Virtual Serial Port Driver vs. Null-modem emulator

There are both advantages and disadvantages to using paid or freeware software solutions to address serial connectivity issues. To help you decide which is better for your situation, we present this table that looks at the features of Virtual Serial Port Driver and Null-Modem Emulator (com0com).

Product to compare:
Features list
Virtual Serial Port Driver Electronic Team
Null-modem emulator com0com
Tested version
The proprietary licensing scheme that does not oblige you to expose the complete source code of your own derivative works which are based on or incorporate any part of the program
The out-of-the-box solution that does not require any additional software or drivers
Availability of customer support service assisting in matters related to software usage, installation, and configuration
High-level technical assistance during software customization and integration into your industry-specific products
Regular software updates and improvements
Drivers successfully passed Microsoft Windows Hardware Quality Labs (WHQL) tests and are digitally signed by Microsoft
Any number of virtual serial ports pairs can be created
Full software emulation of real serial port
Hot virtual ports installation - no reboot required after installation, creation or reconfiguration of virtual serial ports
Link between virtual serial ports is much faster than real null-modem cable connection and solely depends on your processor speed
Virtual serial port may have any name you like (not only COMx)
Virtual serial ports are located in Device Manager, thus any software finds the ports
Virtual ports are located in "Ports" group of Device Manager
(all ports)
(only COMx ports)
Possibility to create ports for the current user session only. Allows RDP users to create port with the same name (e.g. COM1) in each user session.
Ports are automatically re-created on system reboot (prior to user login)
Get information about current virtual serial port state, amount of sent/received data
Virtual serial port can have the same name as real serial port (virtual serial port overlapping)
Emulate virtual serial line connection break
Manage port access list, which is used to restrict access to created ports for various applications
Different virtual null-modem schemes are available
Ability to save null-modem scheme as a template
Full support of Flow control (Hardware and Xon/Xoff)
All signal lines supported (DTR/DSR/CTS/RTS/DCD/RI)
Strict baudrate emulation
Make virtual ports available for printers, registering virtual serial ports in Windows Registry so, that they can be selected in Add Printer Wizard
Drivers and binaries are signed by company certificate
No warnings during ports creation on Windows XP
Works on Windows 10 with UEFI and Secure Boot enabled
Virtual pair settings can be changed without the need of closing ports
Virtual pair can be deleted without the need of closing ports
Remove all virtual pairs in one click
Instantaneous ports creation lets working with them even before PnP manager detects the newly added ports
Virtual port properties window in device manager has a tab with port information and statistics
All Windows operating systems supported
Windows XP 32/64
Windows 7 32
Windows 7 64
Windows 10 32
Windows 10 64
Windows Server 2008 R2
Windows Server 2012 R2
Windows Server 2016
Free version available
no (trial)
No Net Framework required for GUI to run
You can enable automatic update of ports’ list, thus you can see pairs created in other user sessions
Possibility to change company in device name shown in Device Manager