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dsdcc

Decodes digital voice protocols from demodulated audio

What it does

Takes discriminator or demodulated audio and decodes the digital voice protocols carried in it -- DMR, D-STAR, System Fusion, NXDN, P25 Phase 1 and dPMR -- recovering both the voice frames and the signalling around them: talkgroups, source and destination identifiers, colour codes. It is a C++ rewrite of the original DSD.

Why you would want it

Amateur digital voice is several incompatible standards and a receiver hears all of them as noise without something like this. For monitoring a DMR repeater's talkgroup activity, or identifying which protocol an unfamiliar signal is using, it is the tool that turns the transmission into something a person can act on.

Before it will work

Demodulated audio at the right level, usually piped from an SDR receiver or taken from a scanner's discriminator output. Level and polarity both matter and neither is obvious.

How it installs

  • apt: dsdcc

Known problems

The AMBE and AMBE+2 vocoders used by D-STAR, DMR and Fusion are patented and proprietary; this decodes the protocol layer, and the voice quality of open replacement vocoders is noticeably worse than a commercial radio's. Encrypted transmissions decode to the fact that they are encrypted and nothing more -- that is by design and is not a bug to report. Listening to what you may lawfully listen to is jurisdiction-dependent and is yours to know.

Keeping it current

  • probe: apt policy
  • strategy: apt_upgrade

Where to get help with the software itself

Edouard Griffiths, F4EXB -- the SDRangel author. GitHub issues at the URL above.

Source: catalog/packages/dsdcc.yaml