I am releasing the first version of my open source (BSD license) digital speech decoder software for Linux/BSD. This is broken into two separate packages, mbelib which describes all of the patent encumbered functions, and dsd which is intented to be patent-free. Source code only is provided for both packages, for educational use only as a written description of how such a decoder might be implemented. Compile or use at your own risk.
It supports P25 Phase 1 and the vendor-specific TDMA system used by Loudoun and Prince Georges County, called "MoTDMA" for lack of a better name.
Any suggestions or code contributions would be greatly appreciated (You can use the gpg public keys in the distribution packages for privacy if desired). I am not a professional
software developer to these packages may not be up to usual open source quality but they should work!
Download links:
dsd-1.0-src.tar Download
mbelib-1.0-src.tar Download
From README:
DSD is able to decode several digital voice formats from discriminator
tap audio and synthesize (play) the decoded information. Speech
synthesis requires mbelib, which is a separate package.
Supported formats in version 1.0:
P25 Phase 1 Widely deployed radio standard used in public safety
and amateur radio.
Full support including decoding and synthesis of speech,
display of all link control info, and the ability to save
and replay .imb data files
MoTDMA Proprietary two slot TDMA system currently being deployed
by several public safety organizations. Frame format
appears to be based on a manufacturer proposal for P25
Phase 2.
Partial support that allows the decoding and synthesis
of speech, and the ability to save and replay .amb data
files. DSD will lock onto an arbitrary timeslot. Link
control info display and the ability to select specific
timeslots may be included in future releases.
Digital Speech Decoder 1.0
Copyright (C) 2010 DSD Author
GPG Key ID: 0x3F1D7FD0 (74EF 430D F7F2 0A48 FCE6 F630 FAA2 635D 3F1D 7FD0)
mbelib 1.0
Copyright (C) 2010 mbelib Author
GPG Key ID: 0xEA5EFE2C (9E7A 5527 9CDC EBF7 BF1B D772 4F98 E863 EA5E FE2C)
It supports P25 Phase 1 and the vendor-specific TDMA system used by Loudoun and Prince Georges County, called "MoTDMA" for lack of a better name.
Any suggestions or code contributions would be greatly appreciated (You can use the gpg public keys in the distribution packages for privacy if desired). I am not a professional
software developer to these packages may not be up to usual open source quality but they should work!
Download links:
dsd-1.0-src.tar Download
mbelib-1.0-src.tar Download
From README:
DSD is able to decode several digital voice formats from discriminator
tap audio and synthesize (play) the decoded information. Speech
synthesis requires mbelib, which is a separate package.
Supported formats in version 1.0:
P25 Phase 1 Widely deployed radio standard used in public safety
and amateur radio.
Full support including decoding and synthesis of speech,
display of all link control info, and the ability to save
and replay .imb data files
MoTDMA Proprietary two slot TDMA system currently being deployed
by several public safety organizations. Frame format
appears to be based on a manufacturer proposal for P25
Phase 2.
Partial support that allows the decoding and synthesis
of speech, and the ability to save and replay .amb data
files. DSD will lock onto an arbitrary timeslot. Link
control info display and the ability to select specific
timeslots may be included in future releases.
Digital Speech Decoder 1.0
Copyright (C) 2010 DSD Author
GPG Key ID: 0x3F1D7FD0 (74EF 430D F7F2 0A48 FCE6 F630 FAA2 635D 3F1D 7FD0)
mbelib 1.0
Copyright (C) 2010 mbelib Author
GPG Key ID: 0xEA5EFE2C (9E7A 5527 9CDC EBF7 BF1B D772 4F98 E863 EA5E FE2C)