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[aprssig] AX.25 'H' flag

Curt Mills archer at eskimo.com
Mon Nov 14 05:00:28 UTC 2005


On Sun, 13 Nov 2005, Curt Mills wrote:

> On Sun, 13 Nov 2005 scott at opentrac.org wrote:
> 
> > Stations monitor and repeat frames that meet the following
> > conditions:
> > 
> > a) the frame is addressed to this station in a repeater address subfield;
> > b) the H bit in its repeater address subfield is 0; or
> > c) all previous H bits are set to one.
> > 
> > 
> > Is that 'or' in B supposed to be there?  Doesn't make sense to me.
> 
> I read it the same way as you.  It's an AND between all three
> conditions.  It's the only way it would work properly.

Oh yea, for preemptive digipeating like digi_ned can be set up to
do, then things change a bit.  Then condition c) need not apply.
That's certainly not in the AX.25 spec though.

-- 
Curt, WE7U.				archer at eskimo dot com
http://www.eskimo.com/~archer
  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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