The reasons to monitor
COM port traffic

Olga Weis May 29, 2025

Working with serial-port devices and apps you may require dedicated software tools to monitor and analyze the activity of your system’s serial interfaces.

Contents

The most common reasons to monitor serial port traffic.
Capture serial port data with Serial Port Monitor.
Redirect COM port traffic with Virtual Serial Port Driver.
Debugging Serial Communication with the Help of Virtual Serial Port Driver and Serial Port Monitor

COM port monitoring applications are commonly used to help identify issues with serial-port devices or software or initiate long-term automatic monitoring of serial communications.

To detect and troubleshoot issues with your COM-port equipment, you need to be able to start a port monitoring session at any time, view all captured data, and save it in different formats. Serial Port Monitor by Electronic Team can help you achieve this.

If you aim to create a monitoring system where data will be collected from one or multiple COM ports and then sent to dedicated applications for further processing and analysis, you can rely on a Virtual Serial Port Driver.

Let’s take a closer look at how COM port monitoring works and what benefits you get with each of the aforementioned solutions.

Comparison Table of solutions to capture serial port traffic

Feature

Serial Port Monitor

Virtual Serial Port Driver

Built-in data visualizers

Displaying data in different formats (binary, ASCII, HEX)

Displaying COM port parameters

Joining data from several serial ports

Redirecting serial port data to one or many serial apps

The ability to start working with ports already opened by other apps

Capture serial port data with Serial Port Monitor

With the ability to monitor COM port traffic, you can promptly identify or prevent problems that may occur with your serial devices or software. Using the dedicated monitoring app, Serial Port Monitor, it’s easy to read and record data going through any serial port available in your system. That means you can quickly test and analyze whether programs or devices connected to monitored ports operate correctly.

Serial Port Monitor is designed to capture the incoming and outgoing data streams from serial ports of virtually any type, including standard onboard ports, software-based virtual COM ports, extension board ports, Bluetooth COM ports, and more.

The app efficiently intercepts and records serial data from any number of COM ports in real-time and saves all monitored data to a file.

Serial Port Monitor allows viewing captured data in different formats by offering Table, Line, Dump, Modbus, and Terminal data visualizers. With this app, you can efficiently capture serial port data received and sent by your serial ports and identify issues in your system in a timely manner.

Here’s how the app works:

1

To start a new monitoring session, open the app and choose Session > New session from the main menu:

2

Select the following in the New monitoring session window:

- The COM ports you’d like to monitor;
- Preferred visualizers to display captured data (Table, Line, Dump, Terminal, and/or Modbus);
- The events you want to monitor: Read/Write, Create/Close, and/or Device Control;

If needed, enable the session options: “Start monitoring now” and “Start in new window”.

3

Click Start monitoring.

Redirect COM port traffic with Virtual Serial Port Driver

You may need to monitor COM ports to track specific events in your communication system and send captured data to multiple recipients at a time. For that scenario, the optimal solution seems to be the Virtual Serial Port Driver software.

This app gives a way to split a real serial port into multiple virtual interfaces that copy the behavior of the real port. All data received by the split port is replicated and sent simultaneously to all virtual ports and devices or apps connected to them.

To redirect serial port data this way, you should create the respective port bundle in the app.

Here’s how to use Virtual Serial Port Driver’s port-splitting functionality to monitor serial port traffic:

Please note that this feature is only available in the app’s PRO edition.

1

Start the app and select “Split” on the vertical menu at the left. Then, click the Split real port button under the port bundle description.

2

Set up your COM port bundle. Choose a real serial port to split and add virtual COM ports that will copy the behavior of the physical port. Add the ports by clicking the “+” button, and remove them by clicking the “-” button.

Optionally, you can enter the preferred bundle name in the “Description” field and enable the strict baudrate emulation option for virtual COM ports.

3

Once done, click Create.

Virtual Serial Port Driver capturing serial port data

4

Now that the port bundle is created, all the data received by the real serial port will be replicated and sent to the virtual ports and devices or apps working with them.

The newly created port bundle will appear in the app’s bundle tree. By clicking the bundle, you can open its info and view data transfer statistics.

Virtual Serial Port Driver SDK

The advanced functionality offered by Virtual Serial Port Driver can be integrated into your software or hardware product.

You can request a 14-day SDK trial and test the port-splitting feature for free. Learn about SDK options by the link.

Debugging Serial Communication with the Help of Virtual Serial Port Driver and Serial Port Monitor

Serial communication can be tricky to debug due to the limited visibility into what's being transmitted or received. When developing serial communication software, you may face various issues, including malformed messages, incorrect parsing of device responses, etc.

Tools like Serial Port Monitor and Virtual Serial Port Driver (VSPD) come in handy to analyze serial port activity and identify any possible problems during the development process.

With Virtual Serial Port Driver, you can create a pair of virtual COM ports. In situations where there are no physical serial ports or devices available for real-time testing, this is especially useful.

Virtual serial ports copy the parameters and behaviour of real ports, allowing you to initiate and analyze serial communication without using a physical serial device.

Paired ports exchange serial data in such a way that everything written to one port immediately appears in the other one and vice versa.

During debugging, you can connect an app that emulates the behavior of a real serial device to one port and your serial communication software to the other.

Alternatively, you can open one of the paired ports with Serial Port Monitor and manually send requests and responses via the app’s Send Dialog to the other port opened with the serial app you’re developing.

Also, Serial Port Monitor provides the ability to reproduce a previously recorded monitoring session back to a serial port.

Here’s how to use this feature.

Once you create a pair of ports with Virtual Serial Port Driver, open one of the virtual ports with Serial Port Monitor and take the following steps:

1

Start a new monitoring session or open a previously saved one by selecting Open session from the Session menu.

2

Then, select Reproduce session from the Session menu.

3

Configure the session settings.

“Use port” – choose the port to which you want to reproduce data.

“Direction”- choose whether to send requests to the selected port (reproduce data that was written to the serial port by the app) or respond as a device (reproduce data that was written to the serial port by the serial device)

“Preserve time intervals” – when enabled, this option allows keeping the time intervals between data packets.

If you would like to substitute the Read/Write timeout events, you should enable the “Custom IO timeout” option. Note that the values are indicated in milliseconds.

4

Click Start.

Using Serial Port Monitor to record a correct communication session and replay it through a virtual port allows you to:

Simulate device behavior.
Send controlled, repeatable data streams to serial applications.
Debug and test flow control without relying on physical hardware.

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Information

Requirements

Requirements: Windows 7/8/8.1/10/11 (32/64-bit), Windows Server 2012/2016/2019/2022, Windows on ARM

Latest version

Latest version: v11.0.1068, Released 14 Nov, 2024 Release notes

The reasons to monitor COM port traffic

Comparison Table of solutions to capture serial port traffic

Capture serial port data with Serial Port Monitor

Redirect COM port traffic with Virtual Serial Port Driver

Debugging Serial Communication with the Help of Virtual Serial Port Driver and Serial Port Monitor

The reasons to monitor
COM port traffic