[aprssig] HT/mic DTMF standards

[Robert Bruninga]

Update to the APRStt table of existing radio DTMF pads:
  
 TH-D7   has 16 with 1=qz   multi-press A=next-letter
 TM-D700 has 16 with 1=qz   multi-press A=next-letter
 TM-D710 has ?? With 1=qz   multi-press C=next-letter
 FT470   has ?? with 7=PQRS any encoding?
 FT-51R  has 16 wiht 1=QZ   any encoding?
 TH-79a  has 16             No Alpha at all. 
 VX-7R   has 16 with 7=PQRS any encoding?
 VX-8R   has ?? With 7=PQRS multipress  "mode"=next-letter
 Cell Phones    use  7=pqrs multipress  PAUSE=next-letter
 Echolink...    Uses 1=QZ   two-digits-per-letter-fixed

 APRStt proposed use 7=pqrs multi-press A=next-letter

If anyone can fill in the missing knowledge. It would be
appreciated.  Or add any other radios that have LETTER
definitions on the keypad.  Particularly, what do the FT's and
VX7R do with the alphabetic keys?  Do they spell some menu
responses?

Notice, that I am leaning towards the final defination for
APRStt as shown above.  The only open item is what key to use
for the "next-letter" key.  I'm leaning towards "A" since all
radios except the D710 are compatible with it, and maybe we can
change the D710 (though it doesn't matter, since APRStt is not
needed with a D710 since it can send APRS directly).

> K1RFD (author of EchoLink) seems willing 
> to consider possibly supporting MULTI-PRESS
> in addition to his two-key method at some 
> time in the future to come more in line with 
> cell phone use... So it looks to me like
> the APRStt standard should be:
> 
> Multi-press(lower case first), with 7=pqrs, and A=next-letter
>
> See the APRStt web page www.aprs.org/aprstt.html  
> It is evolving, so some sections are out of date 
> as we nail these issues down...
> 
> And for ABBREVIATED CALLSIGNS, once the system 
> has received your pre-loaded DTMF fully spelled 
> callsign, then F5SMZ suggests that using the 
> SUFFIX is the least complex way of entering a 
> shorter call as long as it does not conflict 
> with anyone else on that same APRStt frequency.
> 
> IE, "APR" (27A777) instead of "WB4APR" 
> (922444427A777).  Where the "A" key is used 
> as the "next-letter" separator if adjacent 
> letters are on the same key.  
> 
> Bob, WB4APR