[aprssig] An amusing aside (Text Pagers)
Wes Johnston, AI4PX
wes at ai4px.com
Sat Jan 30 15:42:30 CST 2010
I used one of these DTMF devices on my 2nd trip to EU back in the 1990's.
None of the phones had dtmf (all pulse dial) so I couldn't use my calling
card. On the first trip, I had used my trusty Yaesu HT held near the
telephone to enter DTMFs.
Back on Subject.... Yes, the device I was proposing was exactly one of
those piggy back DTMF generator "critters". But it it had a way to guide
you through a message or creation of a packet via an LCD display, great. It
would then squirt out 1200AFSK NRZI data or DTMF. Such a device would be the
sort of thing you'd keep in your go bag. Yes, I know this defeats the come
as you are use the built in DTMF pad on HTs. Like I said in last email, the
uber geeks can enter the correct DTMFs from memory or by hand.
The aprs-tt would then either read back the packet to you (ie ai4px at lat
34.xxx 80.xxx icon jogger, status off duty) or a simple "ai4px packet
accepted" in Majel Barret's voice of course.
Back in the 1980's General Instruments made a text to speech chipset that
would speak when ascii words were fed to it. Is there any comparable chip
available today? Most things I see are the IVR store and playback chips.
I tend to think that DTMF would work better since the device in question
would not be hooked to a mic electrically. If I was going to hook it up
electrically, I'd just use an open tracker or tiny trak in mic-e mode.
I haven't read the APRS-TT page lately, but many repeaters will pass DTMF
tones as long as the first digit is the #. We need to make sure that
aprs-tt can tolerate the leading #.
Dave VanHorn: very good idea of shortening the dead time between digits.
It's one of those "why didn't I think of that" moments.
God help those who do not help themselves.
On Sat, Jan 30, 2010 at 13:07, Alex Carver <kf4lvz at yahoo.com> wrote:
> > From: "Wes Johnston, AI4PX"
> > Subject: Re: [aprssig] An amusing aside (Text Pagers)
> > If we had a way to see the numbers we've entered, or
> > somehow compose a
> > message / posit packet offline, then have a pic processor
> > spit out the DTMF
> > string for us, we'd have a winner. But then again,
> > why not have the little
> > pic processor spit out a normal packet? the answer
> > may be that a 1200 baud
> > AFSK packet can't be squirted in by holding a small device
> > close to a
> > microphone... the DTMF's can. So I could use this little
> > cigarette sized
> > black box with an lcd display on it to compose a position
> > report "off
> > line",then it would build the DTMF tones needed to convey
> > my info. I would
> > hold this near the mic of any radio or HT and vollia.
> > This would be the
> > deal maker. Preprogramming DTMFs in one or two
> > memories is close, but no
> > cigar. Along the same lines, we *could* compose aprs
> > packets by hand, but
> > we all use software to build the packets for us. This
> > should be no
> > different. The true "hacker"/ "uber geek" types can
> > certainly punch all the
> > right DTMF sequence, but to reach the masses, a helper
> > device would go a
> > long way toward general acceptance / useage.
> What you just described is identical to the old pocket dialers that used to
> be sold in places like Radio Shack during the 80's and up to the early 90's
> prior to the true rollout of cellular service when payphones reigned. It
> was a little pocket box with a keypad on it and enough memory for 100 ten
> digit phone numbers. A person would hold the dialer up to the handset of
> the payphone (after inserting correct change) and then recall one of the
> stored memory slots. It would warble out the DTMF tones right into the
> microphone and dial the payphone. Some of the later versions had LCD
> screens on them so you could see what was typed.
> I've seen this written as software for PDAs now, but you can probably still
> find the hardware versions laying around on eBay or other places. I found a
> couple just with a quick search for "Pocket tone dialer":
> http://cgi.ebay.com/Sharp-EL-6250-Dial-Master-Pocket-Calculator-Dialer_W0QQitemZ120524337611QQcmdZViewItemQQptZCalculators?hash=item1c0fcf71cb(wrapped link)
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