Why should I use a virtual COM port?
The main reason that virtual serial ports via Ethernet are useful is due to the limitations forced upon users by modern computer manufacturers. The majority of modern computers have neglected serial ports in favor of the more universally used USB interface. If your computer does have serial connectivity, the number of ports will be extremely limited.
This can pose a serious problem if you use legacy applications that require serial interfaces with which to communicate. It’s not as simple as using a different physical interface on a peripheral device. Without rewriting the code, many legacy programs will cease to operate without serial connectivity. They do not have the ability to adapt to the modified data flow from a USB port.
So using virtual serial ports is a way to protect your investment in legacy serial-based equipment and applications. You can go ahead and buy that screamingly fast new laptop without worrying about the number of serial ports it does or does not have. Simply emulate them with as many virtual serial ports as you need.
Virtual Serial port over Ethernet
Here’s a scenario where you could use Serial to Ethernet Connector to establish communication. You need to access a peripheral device located a considerable distance from your computer. The program that will process the information from the device is installed on your machine, but you have no serial interface. Simply follow this procedure to create a connection with a virtual serial port.
- Download Serial to Ethernet Connector on both the computer that is physically connected to the device (server) and the one that needs to remotely access the peripheral (client). The client machine can be either virtual or physical and needs to be running Windows or Linux.
- Launch the app on the server and configure the connection settings.
- Click the button to create a Server connection which makes the device available over a network.
- Start the program on the client machine and click “Connect” to establish a connection with the previously shared device.
- The client now can exert remote control over the device in the same way as if it were directly connected to it. You have all the functionality of a locally attached device.
The software creates a virtual port on the client machine and connects it to the physical interface of the server computer. It operates as a virtual null-modem connection and emulates all of the functionality and characteristics of the remote physical port.
Virtual serial port over Ethernet Linux
Serial to Ethernet Connector also provides Linux virtual serial port over Ethernet capability. It offers the same functionality as the Windows version of the application and can easily be downloaded to your Linux machine. There are also alternative methods that you use to send serial data over the network using tools that are included as part of most Linux distributions.
One option is to use netcat to pipe serial data. This can quickly become messy as you need to open a separate instance of netcat for each serial connection. You can create a xinetd service to create persisting connections like this:
service testservice
{
port = 5900
socket_type = stream
protocol = tcp
wait = yes
user = root
server = /usr/bin/netcat
server_args = "-l 5900 < /dev/ttyS0"
}
Be sure to change the /dev/ttyS0 to the name of the serial device involved in the connection. This method provides a free virtual serial port over Ethernet solution.
Some other tools that have been tested and can provide virtual serial port over Ethernet on Linux machines are:
- ser2net - Serial to Network Proxy (ser2net)
This utility allows users to connect to a serial port from the network. It is a self-developed program that gives the user a tool to setup and configure serial ports. It is also useful for modifying port parameters as well as controlling and monitoring serial interfaces.
Short for "remote tty”, remtty uses pseudo ttys to establish network connections. Using this tool enables Linux users to enjoy the same functionality of Cisco's Windows-based Dialout application and use direct connections to machines with dial-out modems for faxing and sending messages.
You now have all the tools at your disposal to work with remote COM ports over Ethernet connections. Serial over Ethernet Connector is a versatile tool that can run on real or virtual Linux or Windows systems. It provides an easy way to share virtual serial ports and their connected devices with network-connected users located anywhere in the world. It doesn’t require additional hardware or extensive configuration, making it an effective and efficient solution to the lack of serial ports on modern computers.
