[aprssig] POI engine on APRS-IS (now the ITEM engine)

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Tue Feb 21 11:25:13 CST 2012

On 2/21/2012 10:09 AM, Bob Bruninga wrote:
>> POI.  Also, can we make the [ts] (table symbol) allowed
>> to appear anywhere in the message and if not present,
>> a default symbol will be used.  Special characters are
>> harder to type than characters and if the sender
>> doesn't care, why put them through the agony.
> I prefer the fixed format requiring the symbol in brackets as the 2nd word.
> My assumption is that one only has to enter such an object once, and from
> then on, he simply calls up his last transmitted object and cursors over to
> only change what he needs to change to uplink the next object.  He should
> never have to find the [ and ] keys again and for many applications, the
> symbol will not be changing muchfor a given event.

My assumption is that if there's an arcane syntax like [ts], then nobody 
in the field will remember it to use it the first time.

And if we're going to require it to be the second word, then why not get 
rid of the [] and just make it ts representing the table and symbol.  Or 
optionally just s if they want the primary table.

But my contention is still that it can be optional because the average 
operator in the field isn't going to remember which character represent 
what symbol which is why I proposed making the [ts] optional, allow it 
to appear anywhere (the [] being the key), and default it to something 
like [/.] which is X marks the spot.

And just because Kenwood radios remember the outbound message and allow 
you to edit it doesn't mean that all radios and/or APRS clients do the 
same.  If we're designing protocols, we need the design to readily 
accommodate ANY APRS-capable radio and/or client, now and in the future, 
without making assumptions based on convenience of this or that current 

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

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