[aprssig] APRStt (touchtone) lives

[david vanhorn]

Someone might create a new device, who knows?

Trying to speed it up by shortening the digit time gets you in trouble with
various decoders, even the $$$$$ ones that the telcos use.


On Mon, Apr 8, 2019 at 12:43 PM Robert Bruninga <bruninga at usna.edu> wrote:

> Wow, that is good info.  Though we are kinda stuck with the way our HT’s
> send their DTMF memories.  But it does suggest that making sure there are
> no repeating digits might make something work at higher DTMF speed than it
> would work with repeating digits.
>
>
>
>
>
> *From:* david vanhorn <kc6ete at gmail.com>
> *Sent:* Monday, April 8, 2019 2:28 PM
> *To:* Robert Bruninga <bruninga at usna.edu>
> *Cc:* Peter Laws N5UWY <n5uwy at arrl.net>; TAPR APRS Mailing List <
> aprssig at lists.tapr.org>
> *Subject:* Re: [aprssig] APRStt (touchtone) lives
>
>
>
> FWIW:  DTMF can be sent nearly twice as fast by implementing a simple
> algorithm.
>
>
>
> A typical string of digits contains few repeats.
>
> While the DTMF spec calls out 10dps as nominal speed, with 50mS tone and
> 50mS silent, the silent period is really not used unless you have two
> digits which are the same, as 1234566789 a delay would be required between
> the two "6"s.
>
> I've used this in industrial applications very successfully.
>
>
>
> If NextDigit = CurrentDigit, then apply delay, else not.
>
> If you're feeling a little unlucky, a 5 or 10mS delay between dissimilar
> digits can always be added but I've never seen it be necessary.
>
>
>
>
>
> On Mon, Apr 8, 2019 at 11:05 AM Robert Bruninga <bruninga at usna.edu> wrote:
>
> The way APRS DTMF works is that you have a 4 digit "message" code and then
> a
> 10 digit callsign so that it all fits in a DTMF memory and can be sent with
> a single key press.  Yet each message is attributed to a callsign or
> station.
>
> The 4 digit message code consists of selecting a pre-defined message (1 of
> 99) and then including a 2 digit "modifier"  as in "Runner 43 is down" is
> 0743.  I know this will not work as is for large runner numbers >99, but it
> does work as is for small events with numbers under 100.  But you get the
> point.
>
> All callsigns and station names of 6 characters or less can be accommodated
> in the ten callsign digits.  The callsign part of the string is always sent
> from pre-loaded DTMF memory after keying in the initial 4 digits.
>
> So think about how we can use this capability.  Remember, almost everything
> that has ever been said on ham radio has most likely already been said
> before.  We just need the top 99 for any particular event template.
>
> Bob, WB4aPR
> -----Original Message-----
> From: Peter Laws N5UWY <n5uwy at arrl.net>
> Sent: Monday, April 8, 2019 12:49 PM
> To: Robert Bruninga <bruninga at usna.edu>
> Cc: aprssig at lists.tapr.org
> Subject: Re: [aprssig] APRStt (touchtone) lives
>
> On Mon, Apr 8, 2019 at 10:48 AM Robert Bruninga <bruninga at usna.edu> wrote:
>
>
> > 1.  Runner XX just passed
> > 2.  Female XX just passed
> > 3.  Handicapped XX just passed
> > 4.  EMS is on scene
> > 5.  Need more water
> > 6.  Need checkpoint captain
> > 7.  Runner XX is down
> > 8.  Need EMS
> > 9.  Am at checkpoint XX
> > 10. ....?
>
> If reporting a runner's sex is really needed, can't you just add and M or F
> flag (or H for disabled runner ... maybe Y for runner under some age that
> means something)?  Dunno - not a marathon volunteer (or runner!).
>
> When is the launch expected?  (and yes, I know what the date means - "no
> earlier than")
>
>
> --
> Peter Laws | N5UWY | plaws plaws net | Travel by Train!
>
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>
>
>
> --
>
> K1FZY (WA4TPW) SK  9/29/37-4/13/15
>


-- 
K1FZY (WA4TPW) SK  9/29/37-4/13/15
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