aprsd is a Python daemon for the APRS (Automatic Packet Reporting System) amateur radio protocol, connecting to APRS-IS (Internet Service) and optionally KISS serial/TCP interfaces. It receives and processes APRS packets through a pipeline of duplicate detection, type filtering, and a plugin-based message handler. The system also supports sending messages, beacons, and weather reports, with persistent storage of watch lists and tracked packets. The architecture is modular: client drivers abstract the network connection, a packet factory deserializes raw APRS frames into typed dataclasses, and a threading model handles RX processing, TX scheduling, and keepalive monitoring. Configuration is managed via oslo_config with a sample config generation command. The project is production-grade for its niche, with Docker support, CI/CD, and a documented plugin API for third-party extensions.
Dire Wolf is a software Terminal Node Controller (TNC) for amateur radio packet radio, specifically AX.25 and APRS. It replaces hardware TNCs by demodulating audio from sound cards or SDR receivers, decoding AX.25 frames, and providing network interfaces (KISS, AGW) for client applications like Xastir, APRSIS32, and UI-View. The codebase is a monolithic C application with threaded audio capture, multiple modem demodulators (AFSK, PSK, G3RUH, 9600bps), forward error correction (FX.25, IL2P), digipeating, IGate (internet gateway), GPS integration, DTMF/APRStt gateway, and telemetry decoding. It runs on Linux, Windows, and macOS. The architecture is single-process with multiple threads, using a global event queue for inter-module communication. Key entry points include the main `direwolf` daemon and several standalone utilities (`decode_aprs`, `kissutil`, `gen_packets`, `atest`, etc.). The implementation is production-grade, with extensive protocol handling and real-world tuning, but exhibits some monolithic design patterns and legacy code (vendored regex, geotranz).