COM Port Redirector

Certain serial applications are designed to function properly only when connected to specific COM ports. In most cases, these are the standard COM1/COM2 or COM3/COM4 interfaces. This can pose a problem when your device needs to work with a designated port that is not available on your machine.

A solution to this issue is COM Port Redirector. You can create virtual serial interfaces with a serial port redirector that you can name in whatever manner your application requires.

The virtual port provides the same functionality of a physical interface and receives and sends traffic redirected to and from the real port. Redirecting serial port over a network is one of the primary uses of a COM port redirector. It increases the value of your peripheral devices by making them accessible to any user on the network.

Accessing serial equipment can be challenging after migrating your computing environment to the cloud. Essentially, you need to redirect COM port traffic so it can be accessed remotely through the cloud infrastructure. Serial to Ethernet Connector is a serial port redirector solution that makes it easy to share COM devices in the cloud.

The first step is to identify a server in the cloud infrastructure that has a stable IP address. Set up a connection to this server and install Serial to Ethernet Connector on the machine. Configure the COM port redirector software to enable remote users to access peripheral devices physically attached to the serial interface.

When properly configured, all data traveling through the COM port will be redirected to the cloud where it can be accessed by anyone with an Internet connection to the environment.

Let's imagine that you have a serial printer (or any other specialized COM port device) that is physically connected to a serial port residing on your office Linux computer. This device needs to be accessed from a remote machine located in another room or office. If you have two Linux machines, you should have no problem creating communication with the remote peripheral using the command-line options of Serial to Ethernet Connector (SEC). But did you know that it’s also possible to use the software as a COM port redirector Linux Windows and the other way around? Here’s how you can do this.

To make it clear, by a “server machine” we mean a computer to which the device you want to share is attached directly. Whereas a “client computer” means a machine from which you are going to connect to a shared device remotely.

Before you start, it’s important to make sure that both the client and server computers are connected to the same local network.

As an example, we will share a serial port named “/dev/tty60” on Ubuntu 20,04,2 via a TCP port 5000. The IP address of our Linux machine is 192.168.24.43.

Follow the steps below to provide remote access to the real serial port that has the printer physically attached.

Step 1. Download Serial to Ethernet Connector and install it on your Linux computer.

Note: On Linux, it currently works only as a command-line utility.

Step 2. Create a “server” connection by using the following command:

evesecli add --real /dev/tty60 server --local 5000

where:

--real - COM port type (real/virtual);
/dev/tty60 - COM port (connection) name;
server - connection type;
--local 5000 - name of the TCP port that will be used for the network connection.

Note: By default, the connection will use the RAW data transfer protocol.

Step 3. Activate the connection by executing:

evesecli start /dev/tty60

Step 4. Check the connection status:

evesecli list -s



As we can see, the real serial port “/dev/tty60” is shared and can be accessed via the TCP port 5000.

Once you connect to the shared port from a remote computer, you will be able to check the detailed info about the connection by using the command:

evesecli list -s

Now let’s create a client connection to the remote serial port on Linux from a Windows machine.

Step 1. Download Serial to Ethernet Connector and install it on your Windows PC.

Step 2. Start the app and create a “client” connection.


To do this, click Client connection in the main window of the app.

Step 3 (Optional). Specify the client connection name.

Step 4. Check the box Create as virtual port and select the port name.

Note: To connect from the Windows client to Linux, a virtual serial port should be created on the Windows PC.

Step 5. Select the Raw data transmission protocol.

Step 6. Specify the IP address of the server computer (192.168.24.43) and the TCP port (5000) to connect to.

Step 7. Click Create.


This is it! Now the remote serial printer is successfully connected to the Windows PC via a virtual COM port (COM 1) and can be accessed and operated like it was plugged directly into the Windows machine.

Whether you create a virtual COM port on Linux or Windows, it appears in the system fully emulating the behavior of a real serial interface.

Now, let’s consider a situation in which your serial printer is plugged into a Windows PC and needs to be accessed remotely from a Linux machine.

Step 1. Download and install Serial to Ethernet Connector for Windows.

Step 2. Start the software and select Server connection in the window that will appear.


Step 3. Configure the server connection settings:

• (optionally) Specify the connection name;
• Select the real COM port you would like to share. (The port to which the serial printer is attached).

Note: When setting up a server connection, you should leave the box Create as virtual port unchecked.

• Specify a TCP port to use for the connection to your network.
• Select the data transfer protocol.

Step 4. Click Create.


Once created, you can check the connection details by selecting this connection on the left side:


As you can see, we have an active server connection named “Server COM1”. The shared real port COM1 is open and is listening for incoming connection via a TCP port 5000.

To do this, follow these simple steps:

Step 1. On the Linux machine, download and install the command-line utility Serial to Ethernet Connector.

Step 2. Create a client connection by using the command:

evesecli add --virt /tmp/virt0 client --remote 192.168.24.66:5000

Where:

/tmp/virt0 client - COM port (connection) name;

192.168.24.66 - the IP address of the server computer you are connecting to;

5000 - the name of the TCP port specified on the server side.

Note: In order to connect to the remote real COM port over the network, you should create a virtual serial interface on the client side.

On Linux, the virtual COM port settings should match the Windows real port settings.

Step 3. Activate the connection by executing:

evesecli start /tmp/virt0

Step 4. Check the client connection status:

evesecli list -s


Important: for the correct operation of Serial to Ethernet Connector on both Linux and Windows sides, you should create an exception for the app in the firewall settings.

SerialToIP is a serial port redirector freeware solution that provides the ability to connect to a serial port from a network using TCP socket communication. The tool can be used with either a command-line or graphical interface. The app is a simple implementation of Terminal Server software written in C#. Any TCP/IP network can be used to send and receive data from serial ports, including those of the USB variety.

This COM port redirector is open source and is freely available to be modified to address your specifications. The open source nature of the project means that you get access to the serial port redirector code. The developers have made it point to provide working code that can be easily understood by other technicians with a knowledge of programming serial ports and sockets with C# and .NET. If you are looking for a basic and free serial port redirector, this solution is worth a look.

A virtual serial port can be seen as a form of COM port redirector that operates without dedicated network software support. Creating two virtual COM ports on the same computer enables legacy serial applications to communicate directly without resorting to other methods such as communicating over named pipes.

A virtual serial port redirector should enable the virtual COM ports it creates to emulate the functionality of physical serial interfaces, for instance, to interact with a locally attached peripheral device. Creating the virtual port itself is not a complex task and can be performed by the same type of software that implements physical COM port drivers.

Serial port redirection software enables the user to control data flow by emulating signal lines (DTR / DSR / CTS / RTS / DCD / RI). You can customize the pinout and replicate all serial port parameters such as Baud rate, parity and stops bits to ensure compatibility with all of your serial applications and devices.

Emulating serial ports is extremely useful when faced with a lack of physical COM ports on a computer that needs to connect to a serial device. It can also enable you to establish communication between devices or applications without the need for additional physical connections requiring cabling or hardware.

Any serial program can make use of virtual serial ports to transmit data over a TCP/IP network. A complete client-server infrastructure can be implemented using virtual COM interfaces. The data sharing capabilities and multiple connections of the virtual infrastructure let any member of your organization access legacy serial devices no matter where they are located. Virtual ports can split data streams so that many applications can access the information simultaneously.