Re: Subject: [Discuss-gnuradio] APCO 25

[Dave Emery]

On Sun, Jan 19, 2003 at 06:13:43PM -0800, Matthew Kaufman wrote:
> My original point was that the details of the vocoder were previously
> *unavailable* unless one paid for too much money and signed restrictive
> agreements. Without them, it is hard to build a compatible transceiver.
> If indeed those specs now exist sufficiently that a vocoder can be
> written, implementation is possible by anyone who doesn't care about the
> legal details. And would be a good and useful thing.
> 
> Matthew
> 
> > 
> > Looks like we have a lot of armchair lawyers around here 
> > trying to discourage people from actually doing something.  
> > If you don't want to contribute for whatever reason, then 
> > don't.  Please stop scaring and discouraging those who do.
> >

        As number one obnoxious armchair lawyer on the list, I do have
to say that my understanding has been that APCO would sell anyone who
asked for it an  APCO-25 spec including the IMBE spec for money.    At
one time this was $2 or $3 K for the whole package, but the last I
checked it was only $450 if one was an APCO member and around $600 if
not.  Not overwhelmingly expensive for a spec (try ITU G III fax specs
some time...).

        And at at one time the vocoder spec was available without
restrictions to the general public - apparently other parts of the spec
are restricted to public safety agencies only.  What restrictions exist
on distribution of the vocoder spec at present I do not know, but I
have never heard of anyone having trouble obtaining it.

        I don't know of any obligations to sign restrictive agreements
to read the spec, but there definately restrictive agreements involved
in acquiring legal permission to implement a product based on it.

        And last I heard, the IMBE license extended to APCO did not
include non public safety uses such as scanners (and presumably ham
radio) and it was rumored that Uniden had some tough negotiations to
get a license they could live with for their new APCO-25 digital scanners.
These were not covered under the APCO license.

        I am sure one would pay through the nose if one tried to get
sourcecode of DVSI's reference implmentation (and no doubt sign lots
of NDAs) but the spec does describe IMBE in enough detail to allow
one to have a go at implementing it .... and obviously APCo-25 radios
are around for use in debugging the code... 


-- 
        Dave Emery N1PRE,  address@hidden  DIE Consulting, Weston, Mass. 
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