Generating APRS-IS Passcodes the Easy Way — with Python
If you’ve ever set up an APRS client like Xastir, APRSdroid, or YAAC, you’ve probably hit that one annoying roadblock:
“Enter your APRS-IS passcode.”
It’s not something you can just request or retrieve from a server. The APRS-IS system uses a 15-bit hash of your callsign – and it’s been the same algorithm since forever. While it’s not secure (and not meant to be), it’s a simple gatekeeping measure to prevent random abuse.
📦 9M2PJU-Python-APRS-PassCode-Generator
This tool is exactly what it sounds like – a lightweight, fast APRS-IS passcode generator that:
✅ Accepts any valid callsign, even ones with SSIDs (like 9M2PJU-5)
✅ Supports callsigns that begin with digits (e.g. 4X1ZZ)
✅ Has zero dependencies – just Python 3
✅ Gives you the official 15-bit APRS-IS passcode instantly
✅ Works offline, with no Internet connection
And that’s it. No pip installs.
🚀 How to Use It
git clone https://github.com/9M2PJU/9M2PJU-Python-APRS-PassCode-Generator.gitcd 9M2PJU-Python-APRS-PassCode-Generatorpython3 9m2pju-passcode-generator.py YOURCALLSIGN
That’s all. You can now plug your passcode into Xastir, APRSdroid, or any other APRS-IS client.
💡 Why I Built This
Most APRS-IS passcode generators you find today are hosted as online web tools – meaning you need an Internet connection just to generate a passcode for your own callsign.
I decided to build a fully offline, open-source tool that anyone can use – without depending on any website.
With this Python script, you don’t need to open a browser. You don’t need to visit an online passcode generator. Just run it locally on your machine, and you’ll get the correct 15-bit APRS-IS passcode in seconds.
No Internet required.
No data sent anywhere.
And yes – the code is short, clean, and 100% transparent. Check it out, modify it, or even integrate it into your own tools.
🔐 A Note on Security
The APRS-IS passcode system is not secure encryption. It’s a lightweight check, not a privacy mechanism. You should never treat your APRS passcode like a password – but you also shouldn’t just share it blindly.
This tool helps you generate it locally, without transmitting anything over the Internet.
🧪 Bonus: Want to Hack on It?
Feel free. It’s MIT licensed. Fork it, integrate it, automate it.
You can find the full source here:
👉 https://github.com/9M2PJU/9M2PJU-Python-APRS-PassCode-Generator
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