Tuesday, November 12, 2013 4:00 pm

How to create a virtual serial port

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A virtual serial port is an ideal solution for when a legacy application expects a connection to a serial device port (COM port), but should instead send data over a local network or the Internet. When the legacy application sends data to a serial COM port, it is actually transmitted over a TCP/IP network and back from the network to your legacy application.

Why should I use a virtual COM port?

Most modern desktop computers and laptops no longer have the DB9's that were traditionally used to connect directly to hardware used in commercial or industrial environments. NetBurner provides a free virtual COM port application that transmits data over the network (Internet or LAN) to NetBurner Serial to Ethernet Servers. This saves time and money by allowing you to use your unmodified legacy applications.

Hardware and software required

  1. A serial communications program, such as MTTTY serial terminal.
  2. Virtual serial port software, such as NetBurners Virtual COM Port Driver.
  3. A USB-to-Serial converter.
  4. A serial to ethernet adapter. Any of the NetBurner serial to ethernet solutions will work.

Our test setup


In our scenario the "legacy serial application" is the MTTTY application on the right. We will create a virtual serial port on COM1 which will send data to the NetBurner serial to Ethernet device server. The serial to ethernet device will send the network data out of its serial port (db9). We will read this data using a serial to USB converter. We will again use the MTTTY application to read serial data on COM3. The expected final behavior is that if we send data from one window, it will show up in the other and vice versa.

How to setup the virtual COM port driver

  1. Install the Virtual COM Port Driver software. The default installation directory is: C:\nburn\VComm
  2. Click on "New" in Virtual Serial Port dialog box and click on "Find" to search for NetBurner Serial to Ethernet device IP. The purpose of this step is to fill the Device IP field
  3. Click "Search Again" if device does not appear in list. Click on your device and then "OK".
  4. To verify that the device port (called the "listening network port" on the webpage) is set correctly, click on the configure button.
  5. Set the "Listening network port".
  6. Make sure the in the "Device Port" field is populated with the the "Listening network port" number set in the last step. Also, choose a COM port. Then click "Ok" twice (the "Dialog" window and "VirtualSerialPorts" dialog window).

  7. Open two Multi-threaded TTY windows, one for the USB Serial port, and one for the Virtual Serial Port
  8. Click connect and send data from the Virtual serial port or USB Serial port to confirm data is going back and forth.
Congratulations! You have now setup and tested your virtual com port driver.

Read 33040 times Last modified on Wednesday, November 13, 2013 9:50 am

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