[aprssig] ARPS physical layer

Wes Johnston, AI4PX wes at ai4px.com
Thu Sep 16 08:42:25 EDT 2010


Reall, no... I'm referring to the bit stuffed into the each of the bit
shifted digipeater callsigns.  I wrote aprsdigi as kiss mode
digipeater 12 years ago and found this little idiosyncrasy.  At the
time, there were many mjf tncs and kpc3(nonplus) in the area and my
test bed TNC was a kpc4 dual port.

I've never looked at how AGWPE or other software TNCs do it.

Wes
---
God help those who do not help themselves.



On Thu, Sep 16, 2010 at 08:10, Curt, WE7U <curt.we7u at gmail.com> wrote:
> On Thu, 16 Sep 2010, Wes Johnston, AI4PX wrote:
>
>> You also need to be aware than KPC tncs and TAPR clone tncs treat the
>> "has been digipeated" flag differently.  I can't remember which is
>> which, but one of them marks only the LAST digipeater field, the other
>> marks EACH digipeater.  Your code needs to simply look for the last
>> digipeater marked as digipeated.
>
> Not exactly.  What you're referring to is the asterisks marking the
> used digipeater fields in the human-readable output from the TNC.
> The actual bits in the binary header are treated the same in either
> TNC, as per the 2.0 spec.
>
> --
> Curt, WE7U.                         <http://www.eskimo.com/~archer>
>   APRS:  Where it's at!                    <http://www.xastir.org>
>  Lotto:  A tax on people who are bad at math. - unknown
> Windows:  Microsoft's tax on computer illiterates. - WE7U.
> The world DOES revolve around me:  I picked the coordinate system!"
>
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