# COMTool: a PyQt5 serial, TCP/UDP and SSH debug assistant with a plugin system

> COMTool is a Python and PyQt5 cross platform communication assistant for serial ports, TCP/UDP and SSH, with a plugin API for custom protocols. It installs from PyPI or as a release binary, and its plugin interface is the main reason to pick it over a single purpose terminal.

**Neutree/COMTool** — Cross platform communicate assistant(Serial/network/terminal tool)（ 跨平台 串口调试助手 网络调试助手 终端工具 linux windows mac Raspberry Pi ）支持插件和二次开发

- Repository: https://github.com/Neutree/COMTool
- Website: https://neucrack.com/p/186
- Stars: 2,604 · Forks: 433
- Language: Python
- License: LGPL-3.0
- Published: 2026-09-28 · Updated: 2026-09-28 · Language: en
- Canonical page: https://hysenlabs.com/projects/neutree-comtool

## What COMTool solves for people wiring devices to a PC

A serial port, a TCP socket and an SSH session are three different ways to look at the same problem: bytes go in, bytes come out, and you need to see them. COMTool puts all three behind one Qt window. The README lists serial, TCP/UDP in both client and server mode, and an SSH client as connection types, with the built in dbg plugin handling the basic send and receive operations. The project is aimed at embedded and hardware engineers who move between a board on a USB adapter and a device on the network, and who would rather not keep three tools open. It is written in Python and uses PyQt5 for the interface, which is why the same code runs on Windows, Linux, macOS and Raspberry Pi. The README does not claim a specific minimum Python version beyond the check in setup.py, which raises an exception when the major version is not 3. Everything in the feature list is a checkbox, not a benchmark, so treat the list as scope rather than as a performance claim.

## The plugin model and how data moves through it

COMTool separates the connection from the view. A connection plugin supplies bytes, and a view plugin decides what to do with them. The README names three built in view plugins: dbg for plain send and receive, protocol for custom encoding and decoding, and graph for real time line charts. The protocol plugin is the part worth understanding before you commit. It lets you define your own encode and decode methods and bind shortcut keys to them, with escape character support for sequences such as \r, \n, \t and \x. The graph plugin takes a different route: it parses incoming data using a protocol header you configure, then plots values as they arrive, and it can add graph widgets dynamically and attach buttons that send data on a shortcut. In practice the data flow is connection to plugin to widget, and the plugin is where your framing lives. That is a clean split, and it is also the constraint: if your framing does not fit the header based parser the graph plugin expects, you write a protocol plugin rather than configuring one. The README documents escape characters in both the dbg and protocol plugins, so hex and escaped text are handled without a separate mode switch.

## Installing COMTool and sending your first frame

The README gives two install paths. Binary releases are the recommended route on Windows and macOS, and the source install is recommended for Linux, for plugin users, and for anyone comfortable with Python. On Raspberry Pi the README installs the heavy dependencies through apt first, then the package itself with pip3. The apt step matters because PyQt5 and numpy are large wheels, and the README notes that installing them with the package manager is the easier path when pip fails.

```bash
sudo apt install git python3-pyqt5 python3-numpy
git clone https://github.com/Neutree/COMTool.git --depth=1
cd COMTool
pip3 install . --verbose
```

After that the command is comtool. On Linux, serial access without sudo needs the dialout group, and the README is explicit that a reboot is required for the group change to take effect.

```bash
sudo usermod -a -G dialout $USER
grep 'dialout' /etc/group
reboot
```

For a first real use, open the application, pick the serial port from the auto detected list, set the baud rate, and use the dbg plugin to send a line. The README states that settings are saved on exit and loaded automatically, and that the last selected port is remembered, so the second launch should come back to the same port and baud rate. If your device answers in a custom frame, switch to the protocol plugin and define the decode method there instead of reading raw hex.

## Where COMTool is the wrong tool

COMTool is a GUI application. Nothing in the README describes a headless mode, a scripting interface or a return code suitable for a build pipeline, so it is not a substitute for a command line serial tool inside CI. The SSH support is listed as a client, with no mention of a server, port forwarding or key management beyond what paramiko provides, so it will not replace a full terminal emulator for remote work. The Linux section is candid about a packaging limit: binaries are compiled for Ubuntu only, and the README asks for contributions if you want flatpak or appimage. Arch users are pointed at AUR packages maintained by a third party, which means those packages track the upstream project rather than being released by it. The dependency pin on qtawesome is worth noting: requirements.txt and setup.py both constrain it to a range, so a resolver that has already picked a newer qtawesome for another project in the same environment can fail. On arm Linux, setup.py runs a sudo pip3 install of its dependencies as part of the build, which is unusual and will not work in an environment without passwordless sudo. And the README itself warns that the screenshots may be from older versions, so the interface you see may differ from the images.

## COMTool against a terminal emulator

The obvious alternative is a general terminal emulator such as minicom, picocom or a plain serial monitor. The difference is not the serial connection, which all of them open; it is what happens to the bytes afterwards. A terminal emulator shows a stream and leaves parsing to you or to a script you write outside it. COMTool keeps the stream but adds a plugin layer inside the same process, so a protocol decoder can turn a frame into named fields, and the graph plugin can plot a value from a header delimited frame as it arrives. That is the trade: you get a visual decoder and a live chart without writing a separate parser, and in exchange you take on a PyQt5 dependency, a GUI, and a plugin API you have to learn from docs/plugins.md. If your workflow is a shell script that greps a log, a terminal emulator plus a parser is simpler and easier to run on a server. If your workflow is a person watching a sensor value change while poking at registers, the plugin model earns its keep. The README also lists a terminal plugin for basic terminal interaction, so the emulator style of use is present, but it is one view among several.

## Maintenance, licence and the cost of upgrading

The repository is not archived, and the last push was on 2026-04-24. The most recent release listed is v3.4.1 from 2024-01-28, so the release cadence is slower than the commit activity, and an upgrade from an older release may include changes that never appeared in a tagged release. Upgrading a pip install means reinstalling the package and letting the dependency resolver re-check PyQt5, pyserial, paramiko, pyte, pyperclip, coloredlogs and pyqtgraph; setup.py special cases arm Linux by installing those dependencies through sudo pip3 at build time, so an upgrade on a Raspberry Pi follows a different path than on a desktop. The licence is LGPL-3.0. For most users that changes nothing. If you plan to ship COMTool inside a closed product, or to link it into proprietary code, the copyleft terms of LGPL-3.0 are the thing to read, and that is a question for your own legal review rather than for this article. The plugin API is the other upgrade surface: a protocol plugin written against an older version may need changes if the interface moved, and the README points to docs/plugins.md as the reference for creating one.

## Conclusion

Adopt COMTool if you debug serial or TCP/UDP links and want protocol decoding without leaving a Qt application, and if you are willing to install PyQt5 and pyserial yourself. Skip it if you need a headless tool for CI, because the README describes a GUI application and the SSH support is listed as a client only. Before relying on it, check that your Python is 3.x (setup.py raises an exception otherwise), confirm the qtawesome pin in requirements.txt resolves on your platform, and open docs/plugins.md to see whether the plugin API covers the framing your device uses.

## FAQ

### How do I install COMTool on Windows or macOS?

Download the latest binary from the release page or SourceForge, unzip the .zip on Windows and click comtool.exe, or install the dmg package on macOS. The README recommends the binary route for Windows and macOS and for simple usage. Windows users can also install it with scoop from the Nightly bucket.

### Does COMTool support TCP and UDP as well as serial ports?

Yes. The README lists TCP/UDP support in both client and server mode as a connection type, alongside serial ports and an SSH client. The tcp_udp screenshot in the README shows the network plugin in use.

### How do I write a plugin for COMTool?

The README points to docs/plugins.md for creating a plugin, and lists connection plugins and view plugins such as dbg, protocol, terminal and graph as the built in examples. The protocol plugin is where custom encoding and decoding methods and shortcut keys are defined.

## Sources

- [License: LGPL-3.0](https://github.com/Neutree/COMTool/blob/master/LICENSE)
- [Neutree/COMTool on GitHub](https://github.com/Neutree/COMTool)
- [Project website](https://neucrack.com/p/186)
- [README](https://github.com/Neutree/COMTool/blob/master/README.md)
- [Releases](https://github.com/Neutree/COMTool/releases)

---

Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/neutree-comtool