On Jun 8, 2008, at 9:18 PM, David Donaldson wrote:
Do we think that anyone other then Icom will ever support the mode? I'd love to experiment with it on the birds but until there is competition to drive the price down will that be possible.
Maybe a GNU project?
Dave WB7DRU Minnesota
Sadly, it's basically impossible to make a software version which interacts with D-Star because of the fact that the vocoder they chose to use is encumbered by patents. This is one of the principle reasons that I can't generate any enthusiasm for D-Star, despite having a number of interesting capabilities that would be useful for amateur radio.
The Wikipedia page sums it up pretty well:
D-STAR has been criticized for its use of a patented, closed-source proprietary voice codec (AMBE). [4] Hams do not have access to the detailed specification of this codec or the rights to implement it on their own without buying a licensed product. Hams have a long tradition of building, improving upon and experimenting with their own radio designs. The modern digital age equivalent of this would be designing and/or implementing codecs in software. Critics say the proprietary nature of AMBE and its availability only in hardware form (as ICs) discourages innovation. Even critics praise the openness of the rest of the D-STAR standard which can be implemented freely. An open-source replacement for the AMBE codec would resolve this issue.
The problem as I see it is that there really aren't a lot of choices for low bitrate audio coders. LPC is of course a possibility, and is free from intellectual property encumberments, but it makes everyone sound like a speak n' spell. The speex codec is open, but doesn't really work down into the 2400bps that we'd like to have. There aren't a lot of other choices that I'm aware of. It sure would be nice to find one though: with all the experimentation with SDR, digital voice could be a no-cost addition to radios, and a rich environment for experimentation.
Mark