P25 repeaters

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Wowbagger
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Re: P25 repeaters

Postby Wowbagger » Thu Aug 20, 2009 1:55 pm

These opinions are mine, not Aeroflex's - if you want service info, manual, or other official support please contact Aeroflex directly.

MattSR
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Re: P25 repeaters

Postby MattSR » Thu Aug 20, 2009 8:47 pm

I wouldn't be worried about number 1 - Aeroflex's framework would be vastly different and more mature than OP25/GNUradio since the latter are only part time "enthusiast" type projects. Your analyzers appear to be designed and built/coded to a spec - OP25 is more 'beta' software at this stage, and as you said its a matter of professionalism for yourself also.

Point number 2 is the one that intrigues me - OP25 has been implemented from the TIA/ETSI specs and publicly available information such as the Daniels P25 training manual - nothing more.. Apart from the DVSI stuff, is there anything else that's encumbered by NDA/patents?

As much as we need good contributors, at the end of the day, its a not-for-profit, research project - if its going to threaten your income or career then its simply not worth it. Morally and ethically, you could contribute things are that are public knowledge, but it could be a potential minefield for you if anyone wanted to play hardball.

Cheers,
Matt

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Wowbagger
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Re: P25 repeaters

Postby Wowbagger » Thu Aug 20, 2009 8:55 pm

These opinions are mine, not Aeroflex's - if you want service info, manual, or other official support please contact Aeroflex directly.

MattSR
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Joined: Thu Jul 20, 2006 8:03 pm

Re: P25 repeaters

Postby MattSR » Thu Aug 20, 2009 10:30 pm

OK cool, that puts my mind at rest. I expected as much re the wide pulse/LSM/other proprietary stuff

Yes - ADP algorithm isn't part of the P25 spec, so I would automatically consider that to be proprietary. Here's where it gets tricky though. the Keyfill interface/protocol *is* part of the publicly available spec, and several manufacturers have developed keyloaders to fill P25 radios. Would it then be considered a breach of Motorola's IP to design a KFD that can load a 40-bit key using the TIA102-AACD specs? Since the spec itself is public, I wouldn't think so - all you're doing is loading an arbitrary 40-bit key into a subscriber unit, all the proprietary stuff is done inside the radio.. Just as long as you didn't use the word "ADP" it should be fine..

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Wowbagger
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Re: P25 repeaters

Postby Wowbagger » Fri Aug 21, 2009 7:23 am

These opinions are mine, not Aeroflex's - if you want service info, manual, or other official support please contact Aeroflex directly.

MattSR
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Re: P25 repeaters

Postby MattSR » Fri Aug 21, 2009 9:09 am

Hehe I'm not surprised - just as the P25 CAI evolved from ASTRO VSELP, P25-KFD probably evolved from ASN legacy mode.

In any case, its a very common style of interface thats been documented in many engineering textbooks since before 2 way radios started using encryption... All they're really patenting is the protocol process/opcodes/framing etc...

Cheers,


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