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[aprssig] station capability flags

Robert Bruninga bruninga at usna.edu
Thu Mar 1 01:29:55 UTC 2007


> One thing that has always seemed missing in the APRS 
> protocol is a way to indicate station attributes.  
> Selecting an icon is quite restrictive.  What if 
> it's a digi with a weather station, or emergency 
> power, or an Igate, or all  of the above?  

That is what the STATUS packet is for.  Every station in APRS
has two packet types for permanent identificaiton of their
station.  The POSITION packet that can contain everyting to know
about his position and can also include WX.  In the status
packet is where additional attributes were designed to go.  In
fact, going back to the original 1992 paper on APRS, the Status
defined single letter atributes for just about everything
possible in ham radio and 36 or more tables each one that could
have 36 or more atributes.  The possiblities were in the
billions...

> ... it seems  to me we could get a very limited set of flags 
> by using the TOCALL SSID bits.  A quick scan of my tnc log 
> file didn't show any TOCALL addresses using an SSID other than
0.

That would be a very limited set indeed.  4 bits only.  And the
reason you don't see them used is becaue the TOCALL-SSID is a
special kind of APRS routing (though rarely used).  A tocall of
APRS-7 for example was supposed to be the same as WIDE7-7.
Thank heavens it was rarely implemented...

I sugges thte STATUS is wide open for these kinds of
definitions...

Bob, Wb4APR





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