[aprssig] DTMF encoding

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Wed Oct 1 12:14:43 EDT 2008


Ok, so they don't use pauses for LOCAL entry, what is the APRStt 
proposal for what actually gets stored and/or transmitted from the DTMF 
memory?  If we store the pauses, that can mean up to 4 strokes per 
character or (worst case) 24 strokes for a call-sign, too many for the 
(I've read) 16 digit memory to hold.  If we don't store the pauses, then 
my ambiguity question still stands.

Seems like the deterministic 2 digits per character (12 per callsign) 
seems to win on that front, as much as I'd rather see the cell-phone 
approach because of its (near) universality.

Lynn (D) - KJ4ERJ

PS.  Cell-phones worth the same, BTW.  If you're going to a different 
key, you don't need to wait.  If you need the same key, you either wait 
or hit some other (A/C/whatever) key to force the timeout to end without 
adding anything to the entered string. DEFFE is still really hard to type!

Robert Bruninga wrote:
> The D7 and D700 do not use pauses.  When you change keys (in the
> multi-press system), then that means you are moving on to the
> next letter.  If the next letter is on the same key, then you
> press the right-shift button ("A" key) or the RIGHt Joystick
> button.   Now here is the amazing part.  In the D710, kenwood
> changed the right-shift function to the "C" key.
>
> Bob
>
>   
>> I'm confused... about how using nnnn can 
>> actually get the right letter without programming 
>> pauses into the stream?  For instance:
>>
>> 5554444337775 = KJ4ERJ or was that L4ERJ or JJJ4ERJ?
>>
>> Without a display to latch on the letter and move the cursor
>>     
> on the 
>   
>> pause, the person driving the keyboard has no clue.  Even
>>     
> worse (and 
>   
>> this is the 'nixer, I suspect) without coding the pauses INTO 
>> THE DTMF 
>> STREAM, there's no way that I know of for the receiver to 
>> know what was 
>> actually entered.
>>
>> I was actually leaning in favor of this approach until he 
>> brought this 
>> up.  Seems like the EchoLink folks might have something going 
>> with the 
>> statement that EVERY keystroke is 2 digits.
>>
>> 525140327351 = KJ4ERJ is deterministic at least.  You could 
>> even extend 
>> it to cover lower-case should anyone really want to do such a
>>     
> thing.
>   
>> 525140357654 = KJ4erj based on hitting the E key 5 times 
>> (DEFdef) and so 
>> forth (76=PQRpqr 54=JKLjkl)
>>
>> Lynn (D) - KJ4ERJ - Adding my $0.02 for whatever it's worth.
>>
>> PS.  I really have trouble with the enter and pause with my 
>> last name.  
>> There's at least once voice response system out in IRS 
>> (Internal Revenue 
>> Service, the US tax guys) that requires me to touch tone the
>>     
> first 5 
>   
>> characters of my last name....
>>
>> DEFFE = 3...33...333...333...33# - Positively painful!
>>
>> jimlux wrote:
>>     
>>> Bear in mind when talking about multiple key presses that 
>>>       
>> most devices 
>>     
>>> that use this have some sort of visual feedback (e.g. an 
>>>       
>> alphanumeric 
>>     
>>> display).  I'd hate to have anything like this with no 
>>>       
>> feedback.  Hence 
>>     
>>> directory lookup interactive voice response systems that ask
>>>       
> you to 
>   
>>> enter the name using a single digit for each letter (using 
>>>       
>> the 2=ABC 
>>     
>>> scheme).. Hopefully that "hashes" to a unique identifier 
>>>       
>> that allows the 
>>     
>>> lookup to work. If not, they disambiguate by asking you "do 
>>>       
>> you mean A 
>>     
>>> (press 1) or B (press 2)"
>>>
>>>
>>> Jim, W6RMK
>>>
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>>>
>>>   
>>>       
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>>     
>
>
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