The best Virtual Null Modem Emulators

Need to test your own serial app but have no free COM ports in your system? No worries, with a dedicated software you’ll be able to create as many virtual serial interfaces as you need. Even better, a decent software virtual port driver will help you establish a connection between your virtual COM ports using a virtual null-modem cable.

Probably the most important thing for any user is to choose a solution optimally suited to their needs. Considering that there is a plenty of software tools serving for serial port emulation, in this article we will provide a short overview of the most popular null-modem emulators.


  1. Virtual Null Modem solution by Eltima
  2. Com0com
  3. Free Virtual Serial Ports
  4. Virtual Serial Port Kit

Virtual Null Modem solution by Eltima

Virtual COM Port Driver is used to create compatible serial ports connected via virtual null modem. These virtual COM ports work in pairs, forming a virtual “bridge”: data sent by one application will be instantaneously received at another end of the pair by another application.

The ports created by this virtual null modem emulator appear to your operating system or any Windows application as standard hardware serial ports. In fact, a virtual null-modem emulator not only does not clutter your desk but also works faster than a real null modem. The virtual COM driver can be included in your own software providing a way to create and configure virtual COM ports directly from your application (OEM license).

That is why this Virtual Null Modem software is considered to be one of the most efficient utility available today.

Virtual Serial Port Driver

Emulate an unlimited number of COM port pairs communicating via a virtual null-modem connection. Supports Windows 10 (32- and 64-bit)
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Virtual Serial Port Driver

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Virtual Serial Port Driver

Let’s take closer to Virtual Serial Port Driver benefits

  • Any number of virtual COM ports

With this null modem RS232 emulator, you can create an unlimited number of virtual com ports and assign them any name, including the name of an existent serial port. Created ports are located in “ports” group in Device Manager so that they are visible and easily recognizable by the system. You can define which application can access a particular port, your real hardware serial ports remain free.

  • Real ports settings emulation

These virtual com ports emulate all the serial port functionality, including Baud rate, data bits, parity bits, stop bits, etc. RS232 null modem driver uses advanced Windows kernel driver technology, which ensures WDM, WMI, Power Management, PnP, etc. support. Virtual COM Port from Eltima emulates a serial line break and it is fully compatible with API COM and supports all Windows messages.

  • All signal lines support

The virtual serial ports created with Virtual Serial Ports Driver emulate and support all standard hardware signal lines (DTR/DSR, RTS/CTS, RING, ERROR, DCD, etc.). Similar to the connection via real null modem cable, DTR of the local port is connected to DSR and DCD of the remote port, and RTS of the local port is connected to CTS of the remote port. Moreover, you can choose loopback pinout or customize it according to your hardware configuration.


If you like the idea of using a serial port simulator but are not sure which solution to choose, an open source kernel-mode virtual serial port driver com0com will definitely be a good choice. The program is able to provide a COM interface for device emulation apps. What this means in practice is that a device emulation program connects to one port of a serial port pair while the other port is used by Windows app (that needs to talk to the device). This way, for example, you can share faxes over IP. All you need to do is connect Windows Fax application to t38modem via virtual COM port pair. Com0com support for Windows 10 is another advantage of the app.

See comparison chart of Virtual Serial Port Driver and Null-Modem Emulator


Free Virtual Serial Ports

Ever wished you could emulate custom plug-and-play COM ports and I/O ports interfaced by 16550 UART? Well, that’s what Free Virtual Serial Ports solution is focused on. This free application lets you create a virtual copy of a hardware null-modem cable with DB-25 or DE-9 connectors. The program lets two RS-232 DTE devices communicate with each other without using modems or any other DCEs. More than that, the app works exclusively in user-mode which ensures the stability of its performance.

Free Virtual Serial Ports

After comparing the functionality of all the aforementioned software tools, you can see that Virtual COM Port Emulator by Eltima stands out for its versatility and ease of use. Such advantages as clean and friendly interface, efficient customer support, high level of data protection, possibility to create and remove virtual ports in real-time, etc. make Eltima’s solution an extremely effective tool able to cover a great variety of port emulation needs.

Virtual Serial Port Kit

If all you need is a handy solution for establishing seamless communications between two serial apps, you can try Virtual Serial Port Kit. This software will let your communications programs talk to each other over a reliable virtual COM port connection.

The main goal of the tool is to provide your system with virtual COM interfaces through which serial apps can enable their two-way data exchange. The scenario is extremely simple, the software just creates two virtual serial ports (exact copies of hardware interfaces) on your computer, let's call them COM1 and COM2, and then one of your apps connects to COM1 and the other one occupies COM2. The data transmission starts once the virtual ports are opened on both sides by the apps.

The additional advantages offered by Virtual Serial Port Kit include support for several null-modem pinouts with different handshakes used for the communication process and the ability to emulate loopback plug. Plus, you won’t need to reconfigure all created virtual ports upon system startup, all settings will be renewed automatically even prior to user's logon.

Virtual Serial Port Kit

Virtual Serial Port Driver

Requires: Available on Windows , 5.5MB size
Version 9.0.575 (23rd May, 2019) Release notes
Category: Communication Application