DSDLink is a Go client that connects to a goDMRLink server and decodes received DMR audio using mbelib-neo.

This client:

• Connects to a goDMRLink server using the Homebrew/MMDVM protocol
• Authenticates with the server
• Receives DMR frames from the network
• Decodes AMBE+2 (3600x2450) voice frames using mbelib-neo via CGO
• Outputs decoded audio to ALSA/aplay

• Go 1.16 or later with CGO enabled
• mbelib-neo (installed system-wide at /usr/local)
• ALSA utilities (aplay)

# Ensure mbelib-neo is installed to /usr/local
cd ~/Compiled/DSDLink/mbelib-neo/build
sudo make install
sudo ldconfig

# Build DSDLink
cd ~/Compiled/DSDLink
go build -o dsdlink

Create a config.json file in the same directory as the executable:

{
    "server_address": "localhost",
    "server_port": 62031,
    "password": "passw0rd",
    "client_id": 1234567890
}

If no config file is found, defaults are used.

./dsdlink

The client will:

1. Load configuration from config.json (or use defaults)
2. Connect to the goDMRLink server
3. Authenticate using the configured credentials
4. Initialize mbelib-neo decoder
5. Start aplay for 8kHz mono audio output
6. Receive and decode DMR voice frames in real-time

1. Network Protocol: Uses Homebrew/MMDVM protocol to authenticate and receive DMR frames
2. Frame Processing: Extracts voice payload from DMR frames (33 bytes with 3 AMBE frames)
3. AMBE Decoding: Uses proper DMR AMBE+2 decode pipeline:
   • mbe_eccAmbe3600x2450C0() - Error correction on codeword 0
   • mbe_demodulateAmbe3600x2450Data() - Demodulation
   • mbe_eccAmbe3600x2450Data() - Extract 49-bit AMBE data
   • mbe_processAmbe2450Data() - Decode to PCM audio
4. Audio Output: Pipes 16-bit 8kHz PCM audio to aplay

MMDVM Hotspot → goDMRLink Server → DSDLink Client → mbelib-neo → aplay → Audio

• goDMRLink: https://github.com/SarahRoseLives/goDMRLink
• mbelib-neo: https://github.com/arancormonk/mbelib-neo