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[aprssig] OT: Yaesu to release digital amateur radio gear

Stephen H. Smith wa8lmf2 at aol.com
Fri Jan 6 19:05:57 UTC 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)


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.



Stephen H. Smith    wa8lmf (at) aol.com
Skype:        WA8LMF
Home Page:          http://wa8lmf.net

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