[aprssig] OT: Yaesu to release digital amateur radio gear
Stephen H. Smith
wa8lmf2 at aol.com
Fri Jan 6 14:05:57 EST 2012
On 1/6/2012 1:30 PM, Daron Wilson wrote:
>
>> While the protocol is open, the CODEC is not.
>
> Just for the sake of discussion, is there a P25 hardware codec available for
> free? (since P25 is an open non-proprietary protocol by definition)
NO!
Only part of P25 protocol is open. The over-the-air digital transport of the
data stream, error correction, selective calls to other station(s), group calls
addressed to multiple other stations , setup & handshaking for trunking modes,
console-to-transmit-site interfaces, etc are open standards.
However, the "secret sauce" AMBE (Advanced Multi-Band Excitation) codec used
for voice coding/decoding (that compresses analog voice to a 4.8 or 2.4
kilobits/sec data stream in P25 systems) is NOT! It is the proprietary
intellectual property of DVSI (Digital Voice Systems Inc) who collects a
royalty of anywhere from $20 to $100 PER RADIO.
Further, manufacturers are completely free to add all sorts of proprietary
bells and whistles extensions to the basic P25 standard for things like vehicle
tracking, messaging, etc. I.e. the error-free transport and delivery of data
packets may be open, but the contents of the packets can be locked up in
intellectual property patents.
This is a somewhat similar situation to the $40 to $100 per unit "Microsoft
Tax" that every computer buyer pays if Windows is preloaded on a PC. The
computer hardware is essentially an open commodity standard (that can be built
by anyone from piece parts if desired), but you are most likely going to be
stuck paying the Microsoft tax to make it useable.
Or the way HTML is an "open standard" on the Internet, but Microsoft then uses
the strategy of "embrace and extend" to add all sorts of proprietary extensions
to HTML that only work with the Internet Explorer browser.
>
> And...
>
> Is there any thing about the JARL Dstar protocol that prevents someone from
> developing their own CODEC solution?
It also uses the AMBE codec. In principle, one could reverse-engineer the
codec and homebrew a compatible piece of software. However this is
criminalized in the US by the vile DCMA (Digital Millenium Copyright Act) that
makes it a Federal Crime to reverse-engineer proprietary software. Even if you
create completely new code to duplicate the same function.
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Stephen H. Smith wa8lmf (at) aol.com
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