PyHam AX.25


This package provides a set of modules for working with AX.25 packets in an amateur packet radio environment. The package comprises two functionally distinct components.

  • The ax25 and ax25.netrom modules provide structure definitions together with methods to pack and unpack native AX.25 frames and NET/ROM routing table updates. These modules work on all platforms, and can be used together with the transport mechanism(s) of your choice.

  • The ax25.ports and ax25.socket modules provide facilities for working with the Linux native AX.25 stack. Unlike other Python AX.25 packages, this includes the creation and use of connected-mode sessions, and thus it is not limited to unproto (UI frame) usage.

This package does not include implementations of transport mechanisms such as KISS or AGWPE. However, other PyHam packages do provide this, or you can use this package in conjunction with any other such software of your choosing.

It is expected that developers working with this package will have some level of knowledge of the AX.25 protocol. Those less familiar with the protocol may wish to refer to the AX.25 protocol specification in conjunction with the documentation for this package.


Martin F N Cooper, KD6YAM


MIT License


  • The ax25 module supports almost all of the AX.25 v2.2 protocol. The sole exception is that only modulo 8 control fields are supported; modulo 128 control fields are not yet supported.

  • The ax25.netrom module currently supports only routing broadcasts. That is, NET/ROM I-frame packets are not yet supported.



This package requires Python 3.7 or later.

The PyHam AX.25 package is distributed on PyPI, and should be installed with pip as follows:

$ pip install pyham_ax25

Then the modules you require may be imported with the appropriate subset of the following:

import ax25
import ax25.netrom
import ax25.ports
import ax25.socket

The source code is available from the GitHub repository:

$ git clone


User Guide

The User Guide walks through some use cases for the package, starting from the basics and adding capability as it progresses.


Complete example applications are included, in order that a developer can observe the usage of the package in a real-world scenario.

API Reference

If you are looking for information on a specific function, class, or method, this part of the documentation is for you.


If you have questions about how to use this package, the documentation should be your first point of reference. If the User Guide, API Reference, or Examples don’t answer your questions, or you’d simply like to share your experiences or generally discuss this package, please join the community on the PyHam AX.25 Discussions forum.

Note that the GitHub Issues tracker should be used only for reporting bugs or filing feature requests, and should not be used for questions or general discussion.


AX.25 v2.2 protocol reference:

NET/ROM protocol reference:

About PyHam

PyHam is a collection of Python packages targeted at ham radio enthusiasts who are also software developers. The name was born out of a need to find unique names for these packages when the most obvious names were already taken.

PyHam packages aim to provide the kind of functionality that makes it much simpler to build sophisticated ham radio applications without having to start from scratch. In addition to the packages, PyHam aims to provide useful real-world ham radio applications for all hams.

See the PyHam home page for more information, and a list of currently available libraries and applications.