[aprssig] ax25 v 2.2

[Scott Miller]

For that matter, I don't know of any implementations that exactly follow the
2.0 spec.  They wouldn't work if they did.

2.2.6 Bit Stuffing
In order to assure that the flag bit sequence mentioned above doesn't appear
accidentally anywhere else in a frame, the sending station shall monitor the
bit sequence for a group of five or more contiguous one bits. Any time five
contiguous one bits are sent the sending station shall insert a zero bit
after the first one bit. During frame reception, any time five contiguous
one bits are received, a zero bit immediately following five one bits shall
be discarded.

Read that carefully - it says insert a zero bit after the FIRST one, and
remove a zero after the FIFTH one.

At least they seem to have fixed that in 2.2.  I tried contacting this group
to register a PID and never got anywhere.  Seems like a dead subject to me.

Scott
N1VG

----- Original Message ----- 
From: "Bill Vodall" <wa7nwp at jnos.org>
To: "TAPR APRS Mailing List" <aprssig at lists.tapr.org>
Sent: Friday, January 14, 2005 10:09 AM
Subject: Re: [aprssig] ax25 v 2.2


>
> >
> > The WIDEn-N system is *not* in AX.25 because it is an APRS
> > specific APRS enhancement by some MFRS and APRS
> > software supporters.  In fact, we have made MANY
> > enhancements that the TAPR AX.25 team has ignored
> > in their new spec.
> >
> > We must get them to open their eyes to recognize that
> > APRS is a well established AX.25 application and they
> > are being short-sighted in their new spec... (or at least
> > the one I saw a year or so ago)...  de WB4APR, Bob
>
> Check the date on the "new" spec...
>
>   http://www.tapr.org/tapr/html/Fax25.html
>
> Last touched November 1997...   Far predating any current APRS activity
> and probably the N-N schemes.
>
> It's not an real issue.  I don't know of any implementation using the 2.2
spec.
>
> Bill - WA7NWP
>
>
>
>
>
>
>
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