[aprssig] APRStt (APRS touchtone DTMF)

[Ray Wells]

Robert Bruninga wrote:
>> How are you going to differentiate the DTMF 
>> tones used for this from the repeater control tones?   
>>     
>
> Good questions.  I have tried to get people who know these codes
> to provide the best recommendations.  Best we have come up with
> is to begin each APRS string with ##A or ##B or ##C depending of
> the APRS application.  The ## in many repeaters tells the
> repeater to ignore the following tones.  THen two of them
> improve that probabilty of detection.  The A or B or C indicates
> the type of APRS code to follow...
>
>   
Guard the repeater control functions with a unique CTCSS tone and a bit 
of logic.

Ray vk2tv
>> 1. Most repeater owners who use DTMF control 
>> guard them very  carefully.  One wrong tone can 
>> cause the repeater to go crazy, meaning you 
>> might have make a trip to a mountain top 
>> or restricted access building.  They are not 
>> universal, and many poeple will be suspicious 
>> if you ask for them out of the blue. 
>>     
>
> Yes, only the existing repeater sysop knows if this application
> will be good on his repeater or better to be placed elsewhere.
> There are so many unused repeaters, that there are plenty of
> places to put them.  Actually, APRStt was mostly designed for
> its own frequency at an event or special purpose.  It should not
> be placed on a repeater that would have problems for it.
>
>   
>> 2. Some repeaters strip DTMF off, others do not...
>> 3. How will I know if a repeater in an area 
>> uses this? Is  this going to be in ARRL 
>> repeater directory, or sent on APRS?  
>>     
>
> Yes, it will show up on every APRS map, or FINDU, or whatever.
> The APRStt engine will appear on all maps with its special
> APRStt symbol and frequency so that everyone can tell where it
> is...  But of course the DTMF user doesn't see the local APRS
> map, so you are right, it will be in directories, and it should
> be included in the voice announcement.
>
>   
>> I don't think you want to just blindy try 
>> sending DTMF on a repeater without asking 
>> a local user. 
>>     
>
> Yes, that is a big concern.  These are all issues we need to
> deal with, but at least now finally we have the mechanism.  Now
> we see how to implement it..
>
> Glad to have you on board and helping...
>
> Thanks
> Bob, WB4APR
>
>   
>> Re: [aprssig] APRStt (APRS touchtone DTMF)
>>
>>     
>>>> APRStt coming soon!
>>>>         
>>>>  but this will be a new version that
>>>> runs under windows using only the sound 
>>>> card for both DTMF decoding and Voice-Back synthesis.
>>>>         
>>> Ehhh...is this going to be available on platforms 
>>> that are suitable for unattended operation? (sigh)
>>>       
>> See www.aprs.org/aprstt.html
>>
>> Bob, WB4APR
>>
>>
>>     
>
>
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