[aprssig] OT: DV Dongle a D-Star codec on USB.

Scott Miller scott at opentrac.org
Tue Jul 8 13:07:44 EDT 2008

We've been through this a bunch of times.

The difference is that it's not just that you can only buy the chip from 
one place - you can't get the specs on how the encoding works, and you 
can't do it yourself without being sued, even if you did figure it out.

Every other proprietary part in a radio (even the D-STAR radios) can be 
replaced by some other part or combination of other parts.  You have 
absolutely no options with AMBE.

Again, it's not a technical problem, it's a legal restriction.

To take your example of a DSP chip - you can buy any DSP chip you want 
and perform the same filter operations with it, you can do it with a 
general purpose processor, you can do it in an FPGA, or you can 
implement it in discrete TTL logic if you really want to.  For AMBE, 
your options are: 1. Buy an AMBE2000 chip, 2. Pay to license the AMBE 
CODEC (hundreds of thousands of dollars at least, by all reports).

Even if those DSP chips you mention were doing something secret (or 
patented), it wouldn't be a big deal because if you're running SSB 
you're still able to communicate with other SSB rigs regardless of how 
spiffy your filters are.  No one else would have to worry about it.  But 
to operate on D-STAR, you pay your money to DVSI or you don't play.

Let me say that again - Digital Voice Systems, Inc gets money for every 
D-STAR compatible radio sold.  You CANNOT build a D-STAR compatible 
radio without DVSI-licensed parts or IP.

It's a very, very sad state of affairs for amateur radio that we've 
decided it's ok that we don't know how critical portions of our radios 
work and aren't allowed to find out even if we're so inclined.


John Habbinga wrote:
>>> Just that the DVSI
>>> AMBE2000 chip is I guess a single uniquely sourced part.
>> Add to that: proprietary, closed source.  IMO, it has no business in ham radio.
> ???  What ham radio on the market today doesn't have a piece of
> proprietary hardware in it?  That new IC-746 Pro you just bought, I
> guess it has no business in ham radio, the DSP chips in there are
> proprietary!
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